I answered because I too run a large vBulletin site which probably would have been better served by QA. They are related but different and, IMHO, while my site may be better suited for QA, does it really make sense to cannibalize my own content repository by creating yet another one?
If you could convince me of a reason to do it, I might. But at this point I think they will steal traffic from each other and be more of a hassle than it's worth.
Drupal, on the other hand, is a completely different matter. QA is not a CMS substitute for articles, wikis, etc. There is built in Wordpress integration which is a great piece of software but very different.
To answer your question more fully, I did a search around here and the answer to vBulletin integration is a solid no and some others said that it isn't happening. I wasn't offended by the negative mark, moreso just that you wanted yes/no and seemed a bit dismissive. Not offended, sometimes much gets lost in translation of QA... or QA being used in a message board forum style. ;)