Using two standard full-length cards is just lazy design (even if he made it a point to use standard components). The GPUs should be on boards like they are on the current MacPro and attached to the monumental heatsink. This add two fans to a design that absolutely doesn't need them. The SATA disks also seem misplaced - it should extend PCI-E storage or, even better, DIMM flash modules: big Xeons have 4 memory channels per socket, enough for letting a couple of those go to storage. Having one single bus for everything makes the machine much neater.