Warforged
by Blacky the BlackballPrime Requisites: Str & Con
Experience Requirements: As a Dwarf
Max Level: 36 (assuming you're using the extended XP tables for Dwarves)
Hit dice: d8 per level until 9th, +2 per level after that.
Attacks: As a Dwarf
Weapons: As a Dwarf
Armour: See Below
Saves: As a Dwarf
Special Abilities: See Below
Artificial Body: Warforged have an artificial body made from wood, metal and other materials. Their internals are a mesh of clockwork and tubes containing lubricating fluids. Because of this artificial body, warforged do not need to sleep and are immune to poison, disease, sleep, paralysis, nausea, fatigue and exhaustion.
No Healing: The artificial bodies of warforged do not naturally heal. A warforged does not heal damage by resting, and can not be healed using the First Aid skill. Warforged can still be healed by magical means, and the Craft (Warforged) skill can be used to do minor field repairs (using the standard rules as if using the First Aid skill on other characters).
Armoured: The outer plating of warforged bodies is equivalent to leather armour and automatically gives them a natural armour class of 7, but they cannot wear additional armour on top of this. A warforged can have its armour plating upgraded and replaced with better armour (including magical armour that has been found), but the upgrade process takes a week and requires access to a blacksmith's forge and tools. A warforged may upgrade its own armour.
Fists of Steel: The fists of a warforged are heavily weighted and this allows the warforged to strike with them as if wielding a war hammer in either hand. All the normal rules for wielding a war hammer apply (including the advantages of Weapon Mastery (War Hammer) if bought, and off-hand penalties if the warforged strikes with both hands) with the exception that the warforged counts as unarmed for the purposes of opponents' Weapon Mastery and it cannot be disarmed. The presence of the weights does not stop a warforged from wielding other weapons or shields (it still has fingers), but a hand that is wielding something else can't make a hammer attack. A warforged can have its fist weights upgraded and replaced with magical ones but the upgrade process takes a day per hand and requires access to a blacksmith's forge and tools. A warforged may upgrade its own fist plates.
This is basically the same as yours, except that I've made upgrading the armour inconvenient rather than expensive. The "Fists of Steel" ability might sound overpowered; but if you read it closely, apart from the inability to be disarmed it's actually no better than simply spending 10gp buying two war hammers during character generation. Plus, magical warforged fist plates aren't going to be that common an item to find (unless you loot them from the corpses of other warforged, of course).