SEARCH
these are separate applications your going to have a search under each one. Just my opinion. I do not see this changing. Kens example is a little trickery you can see. These are all there own searches he simply has altered his forum search template to include specific forms for other applications on his site.
USERPROFILE.
Yes same thing however in future versions we can possibly look at using some sort of
vb plugin modification for that aspect to show the stuff solely in vbulletin.