MWave sells barebones systems. Only thing is they include a floppy drive but you pick the case, mobo, cpu, etc.
You choose the motherboard, cpu, ram, & optical drive (if you want one) and it's assembled and tested. Anything else in your shopping card is shipped separately. If you want the other items in your cart installed and tested, they charge a $79. fee.
Their prices are comprable to Newegg and all the parts are warrantied by them for 1 year.