1,1 Mac Pro here, installing on to a Windows-only hard drive with two partitions (both NTFS, one with the W7 beta, the other with my Windows files).
I got the "type 1 or 2" prompt with x64 Windows 7, reburned and had all kinds of trouble getting the thing to install. First time burning with the modified image, it got almost to the end of the install process and hung up. Trying again, it would restart a couple of times and then complain that it had restarted unexpectedly and couldn't proceed (eh?). Finally, I got it to install by messing around with partitions. That worked well until I tried rebooting into Windows a few days later, as the install was hosed and Windows refused to boot.
I've given up on the x64 version and have managed to get the x86 version working perfectly. Of course, I can't use all 4GB of memory in the computer, but at least the thing works. I have no idea whether it uses EFI to boot, but the boot process looks a lot like the XP one (up to the initial loading screen), and takes a similar amount of time.