You misread the original post. Paralllels have always said it would be included in the next FULL release, not the next release of the current version.
Out of curiosity, why do you want to run Vista? I can't figure out why someone would want to run it in Parallels, unless perhaps you're developing or testing for it. Other than that, most of the best new features (like Aero) will not work in Parallels, and you'll essentially be running the latest service pack of XP.