Quote - What about a dual boot with XP X64 on one partition and Linux on the other? Would that work?

It should work fine.
I have a PC with 32 bit XP and 32 bit Linux on separate physical disks in a dual boot and haven't had any problems I'm aware of yet.
Putting them on separate partitions on the same physical disk shouldn't cause problems, but I'd do some more checking into it first before doing that on my main machine.