8-16 core Mac Pro with Intel Nehalem-based 32nm processors at 4GHz+, Common Systems Interface instead of FSB, PCIe2.0 with 4 x16 slots and 4 x8 slots, 8800GTX and X2900XTX, and something like those previously rumored Final Cut Extreme co-processing cards, dual Blu-Ray/HVD (i mean holographic versatile disc, not HD-DVD) writers, SATA 6Gbps and SAS HDD connections, 10TB+ internal storage at insane speeds, two 4-port bootable eSATA and SAS controllers, Fibre Channel, dual 10-Gigabit ethernet, HD-SDI capture card with ProRes 4:2:2 hardware encoding, Wireless and wired USB, Firewire 400, 800, and 1600 😀
Oh, and at least 5TB of the internal storage would have to be SSDs.
And it has to be quiet. very very quiet.