I think a warforged can be anything, I know the things changes in 3.0 rules which allowed for things like gnome monks so at a guess (and I could be wrong) warforged could be anything but would make very very very very very very poor rogues due to all the squeeking and grinding.
Warforged can be healed well by wiz and sorc with the "repair item" or some such spell but a normal heal spell does only do half (as zed said).
Main thing (for my money at least) about warforged is the fact they are constructs so while they fair better with things like poison stick a rust monster into the mix and it could get hairy (as the constructs are made up of if not entirely but a large part being metal)
Mellee class does sound found with left click swing, right click block with shield thing, I might make a halfling bard as well if only cos I never really got on with bards in pnp, oh and maybe halfling sorc if there aren't many casters kicking around.