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#21
Yes, this should work. We won't know for certain certain until RTM comes out, but various people in the know say it will.
That's correct-ish. If you want to do an in-place upgrade, then no, you can't upgrade vista ultimate with 7 pro. However, you should be able to use the installed copy of vista ultimate to allow you to format and install clean (either over the top, or alongside) using the upgrade key and a dvd boot of windows 7 pro upgrade.
Nothing is 100% certain until RTM comes out and we can try it for ourselves, but all the evidence indicates that 7 upgrades will work the same as vista in this regard, so should be a safe enough bet.