I have long doubted this is really possible to do without terrible performance consequences, due to the way vBulletin's CMS was written, and there is no more development on it to request any refactoring or new hooks. VaultWiki 4 has new features that can be used to replace vBulletin CMS anyway, and vBulletin 4's CMS is on its way out along with the rest of vBulletin. Thus, I'm rejecting my own suggestion.