I tried messing around with a directory structure like that a while back. You'd have to make sure that every reference to an external vBulletin file like
PHP Code:
require_once('./global.php');
was changed to something like
PHP Code:
require_once('../home/global.php');
The problem I ran in to was that it expected files referenced by global.php to be located in places that they aren't...
I'm sure it's possible, but you'd have to have someone more experienced in PHP tell you how to do it. With the new 2.1 version they changed some of the integration code and I read something about being able to put your directories wherever you wanted, but I haven't tried it yet. That's something you may have to ask about in Menalto's forums.
With the user album thing, are you talking about forum attachments or something else? As far as I know there's no way to have uploaded attachments be put directly into a user's photo album.