I would like to half a Mac Pro

Rob Griffiths at MacWorld has built himself a Mid-Mac from the ground up. It's certainly a tempting proposition, what with the Psystar kurfluffle and all. As one of the commenters on the MacWorld article says, the machine I would like to get is about 1/2 of a Mac Pro. The Pro is a neat machine and all, and pretty powerful, but ultimately it is more than I need and a lot more expensive. Apple, make a small tower machine that's similar to the iMac in capability but expandable! Thanks.