These new machines are a ripoff period, compared to what you got with the previous models the new Mac Pros replaced. $200 buys a ton more performance of a octo 2.8 penryn vs the new nehalem quad 2.66Ghz if your app can deal with eight threads (wooo handbrake!).
I'm beginning to wonder if Apple is charging a premium. Intel isn't even supposed to officially launch the Xeon nehalem chips until the end of March. Maybe we see a price adjustment downwards after that and Apple sees how much less Dell, HP, etc are offering their comparable workstations for. Or we all ridicule Apple for being $1,000 over a comparable machine from Dell.
Hopefully 10.5.7 allows people to build hackintosh i7s at home and you can have one cheap.
Considering that the drivers will be there, it's a pretty large assumption that it will...unless Apple got rid of the holes by requiring an EFI ROM on the video card.