Just because I'm on vacation doesn't mean that "geeking on the 'puter" stops. I'm happy to report that I was able to successfully install Windows Vista RC 1 (Build 5600) on my MacBook using Parallels (Release Candidate, Build 1898). This is the first time I've been able to make this work. There was no magic involved, the latest release of Parallels offers Vista as an "experimental" option in the drop downs. I mounted the ISO image in the virtual machine, booted and installed.
It works just fine. You don't get Aero Glass, but you do get Aero. Haven't played with it much, don't expect I will until I return from vacation. However, I'm glad this configuration finally works.