Hey Max,
About the dongle. I have exactly the setup you were talking of now. I got a dongle and transferred my license to that, and I can now boot to either platform on the same license. And I'm on an educational license, so I am sure you could get it done.
Maya works fantastically on XP, as has been mentioned, and like you it is the only reason I have installed XP in the first place. Dont actually relish the idea of Windows on a Mac, but for the performance in Maya I'll get into it.
It took a little hassle to get this arrangement together, but I am sitting happy now, and can wait (for however long it takes) until Autodesk gets a UB version out.
good luck to you,
mic