I noticed when I tried to make a warforged Monk that you could still buy the Mithril/Adamant skin options...but these count as armor and make you basically a non-monk.

There should either be a way to "buy off" the "counts as armor" part of these feats later (via additional feats that do nothing else, for example) or a warning "Purchasing this feat will prevent most of your Monk abilties from functioning" I haven't made a Warforged mage or other caster yet, but I'm assuming these feats will also mess up those classes...

Also, how about making "female" warforged have a more lithe, femininine looking "Chasis" - Slender waist, less bulky arms and legs, and a "front porch" will make the female sounds the character makes a bit less silly.