Personally I wasn't thinking of a mini-tower, just a cheaper incarnation of the powermac. Something with the same flexibility of a powermac, with a slightly smaller form factor, in the $1500-$2000 range would be ideal. $2499 is just too much of a premium for flexibility.
Could be done with desktop hardware (p35 / x38 mainboard), ddr2 (dirt cheap) instead of fbdimm and such. I would welcome such an entry level model bc it wouldn´t be entry model at all. QuadCore Penryn, 8Gig DDR2 cap, possibly 8800 /3870 VGA option. Apple can definitely do it for 1500. Whether they do it is another question.