For defilers especially the quest to be an advanced being should involve a lot of traveling to ancient ruins etc. or sneaking into SK's fortresses looking for clues and pieces to be able to cast the spell. It might be easier for would be avangions if they can get an AB on side.
*Edited to correct name of SK.
(depending on how you play Abalach-Re, as an honest lover of the forest, or a conniving user)
Lalali-Puy. And she's a treacherous female dog.
Otherwise, I presume that the SKs have simple permanent epic spells cast on their cities, telling them when an artifact or epic being enters their realm. Dregoth has one such spell in DA. Nibenay is also able to sense artifacts in one of the ToO novels.
The transformation process making you and AB would, IMO, always need to be done far away from the SKs or other ABs, so you don't attract attention.
Me and Seker have it that Farcluun was a high up royal defiler, a favourite of Abalach-Re, who came close to attaining the levels necessary to become a dragon all under the eyes of the queen. She knew he was powerful but planned to have him killed...except he was smart enough to know when to dissapear from under her radar.
Attaining AB status in a city controlled by another AB is impossible if you're turning into a dragon...too many dead, you see, plus that 1,000,000 Cp focus structure is kinda difficult to hide.
Otherwise, I presume that the SKs have simple permanent epic spells cast on their cities, telling them when an artifact or epic being enters their realm. Dregoth has one such spell in DA. Nibenay is also able to sense artifacts in one of the ToO novels.
It is almost scare Pennarin - but I was thinking the same thing - to the point that I started dreaming up a new spell for this. I do not know if it would be epic, but it will be much more then your standard alarm spell that is for sure.
IIRC, the Sks can, through wards set in the city, detect if another SK was in their city too - I thought I seen a mention of this in one of the books or in an adventure, I could be wrong though.
Lalali-Puy. And she's a treacherous female dog.
Is this a supported view? As far as i remember she could go either way.
She was behind the Forest Queen adventure? and did she show her true face in there?
She still practices Defiling magic, and she's still doing the Dragon metamorphosis.
She just has a different strategy for conquest than the other Sorcerer Monarchs.
Wait untill I'm an epic wizard, powerful enough to kik a SK in to submission...
Wile the advanced being are powerfull the general sistem the 3.5 editoin functions guarants that 5 levels of advantage over any enymy are enough to best him with relative ease:
So, assuming Hamanu a total ecl 40 critter any pure wizard 45 will happly go to Urik and begin the process by extracting the spell from his broken mind via epic domination spells...
well if it was my nek at risk being caught in the transformation, the best way to do it is to wait.
Wait untill I'm an epic wizard, powerful enough to kik a SK in to submission...
Wile the advanced being are powerfull the general sistem the 3.5 editoin functions guarants that 5 levels of advantage over any enymy are enough to best him with relative ease:
So, assuming Hamanu a total ecl 40 critter any pure wizard 45 will happly go to Urik and begin the process by extracting the spell from his broken mind via epic domination spells...
The problem with your post (aside from the gross spelling errors) is that you assume the SK's to be standard NPC characters where you can by default defeat a creature that is lower CR than yourself. You fail to realize what the SK's really are, extremely paranoid, greedy, self confident beings that deposed the most powerful being Athas has ever known. Now that there are only three left, I would certainly think they would be even more paranoid and actively seek out those who would pose a significant threat to their survival (within the confines of their territory at least).
In short, just because someone is more powerful than an SK in one area, does not mean they will be pushovers as you suggest.
These are (or were) men and women who survived centuries of constant warfare - so there is no way IMO that someone is just going to surprise them - they would have known about anyone gaining huge amounts of power and either put things in place to neutralize them as a threat, or made them an ally.
The SKs are not dumb and should not be played that way.
and there are five, not three
Well, three on the Tablelands that most people know about - and actually there would be 7 then - Oronis, Drasky, the Oba, Nibenay, Hamanu, Andy (who is only trapped in the Black - not dead) and Dregoth - so :P
What do you have now my student. Know that my powers in the Dark Side are greater then you could ever imagin. 
Well, three on the Tablelands that most people know about - and actually there would be 7 then - Oronis, Drasky, the Oba, Nibenay, Hamanu, Andy (who is only trapped in the Black - not dead) and Dregoth - so :P
And some might say that Kalid-Ma is merely in an eternal slumber in Ravenloft being guarded over by a chick that doesn't know the meaning of "Let's just be friends."
well if it was my nek at risk being caught in the transformation, the best way to do it is to wait.
Wait untill I'm an epic wizard, powerful enough to kik a SK in to submission...
Wile the advanced being are powerfull the general sistem the 3.5 editoin functions guarants that 5 levels of advantage over any enymy are enough to best him with relative ease:
So, assuming Hamanu a total ecl 40 critter any pure wizard 45 will happly go to Urik and begin the process by extracting the spell from his broken mind via epic domination spells...
I am a fan of "Sorceror Monarchs as a plot-device" sort of outlook, and if I deem that the players are "suitably prepared" to take one down... I'd pretty much set it to about seven to ten CRs above the party. If you just waste the bad-guy, it'd be really anti-climactic. Believe me when I say that it isn't very fun.
As for the original question... I'd say that such beings would probably be far away from the cities... I might even go as far to say that they never come anywhere near the cities. Depends, though, I suppose.
Avangions would certainly be welcome in Kurn and maybe post-pentad Tyr, for example. Cities without their sorcerer monarch might be viable for advanced beings to inhabit... though not in much of a public capacity, I'm sure.
Although I don't think you could build your Dragon Structure in the city. I doubt that the cities would approve licensing for such a structure anyway.
The problem with your post (aside from the gross spelling errors) is that you assume the SK's to be standard NPC characters where you can by default defeat a creature that is lower CR than yourself. You fail to realize what the SK's really are, extremely paranoid, greedy, self confident beings that deposed the most powerful being Athas has ever known. Now that there are only three left, I would certainly think they would be even more paranoid and actively seek out those who would pose a significant threat to their survival (within the confines of their territory at least).
In short, just because someone is more powerful than an SK in one area, does not mean they will be pushovers as you suggest.
The problem with your post (aside from the gross errors in counting the SK) is that you assume the CR system is here just for flavour and does not ipact in any way, say, in an assassination plot.
You failed to realize what the extremely paranoid, greedy, self confident beings that deposed the most powerful being Athas has ever known, part of your description is already accounted in the CR number of said SK, wile the armies and the pletora of equipment at their disposition isn't, the CR level takes in account the objects carried (that is what matters during an assassination attempt)
Kalthandrix sustains that SKs are not dumb and should not be played that way, and I agree, but the same cud be said about the true dragons in other worlds, where, yet, dragonslayers abound (even successfll ones!)
Even a paranoid and powerfull dragon in the end is going to succumb to anyting exeding his CR by 5 or more levels (this is the system and is also quite realistic) it does assume a fair fight, but deviousness cuts both Ways.
I am a fan of "Sorceror Monarchs as a plot-device" sort of outlook too, and the only way to mantain them that way is to guarant them a CR too high for your party as StakeTeriyake stated
:D No need to defend the poor SKs, evryone loves them!:D