Will running a p35 in Crossfire be severely limited in performance to the x38/x48? What about for upgrade purposes? Also, why DDR2-1000 over 800?
I am also really worried that this is going to go over my absolute maximum of 1500 (must include shipping).
Shipping from the Egg is usually 50-75.
P35's are severely limited with CF because the one card is on 4/1. The first card runs fine. The only P35 that does CF well is the Blitz Formula. It has the ability to split it's PCI-E slots to run as 8/8 which doesn't bottleneck unless you're running dual 30" monitors.
Get the DFI DK X38. it's cheap and runs great. I suggest getting two HD3850's. Put them in CF, and you're set. They overclock like crazy too. A cheap case like the CM690(looks great IMO)
You could probably get away with a Corsair 550VX, but a 650 would be a little safer. The PC Power and Cooling 610 is the best if you can squeeze in the cash.