Yeah, it's 64bit Win10. From what I've seen online, if you can get it installed, it's possible to use a custom EFI bootscript to load the windows bootloader, but the trick is getting windows to install on a GPT partition from within the BIOS session.
Edit: I've thought of getting a 4,1 or 5,1 post Nehalem Mac Pro, but it's just not worth the money to me, unless prices have come down? And then I'd be stuck with a 3,1 and I'm too much of a packrat to recycle it, but it's not worth much to sell.
Edit2: Alternatively do you know of anything that can clone my boot disk to the new SSD? The hybrid GPT/MBR is what worries me with most software.