SOLVED
I basically discovered Windows XP is a big whiney bitch and no matter what I did it was looking for a valid install on /disk0. I couldn't get it to point to /disk1.
My only option was to make Windows XP the primary boot device and use the Vista bootloader to load Mac OS X. I used EasyBCD 2.0beta64 and added a Mac OS X entry. Because my mac drive is GPT, I clicked EFI (default), not MBR. I tried both with and without Custom Drive Number. It didn't seem to make a difference.
Save changes and reboot. Now you're presented with the stock darwin loader. It gives you two seconds to press a key then asks for 80 or 81. Since my mac HD is now /disk1 I have to type 81 and hit enter. This is unsatisfactory.
FINAL SOLUTION.
Download Chameleon 2.0rc3 and copy "boot" to your XP drive. Place it in C:\NST. Rename nst_mac.efi to nst_mac.bak Rename boot to nst_mac.efi.
Now when you boot the vista boot loader can load windows XP or go right into Chameleon 2.0. Really great feature!