Has anyone seen a successful WordPress/VB integration yet?

[Fribble]

I'm thinking about cutting my scripting teeth on getting WordPress and VBulletin to work together so I can offer a nice, integrated blogging/journal solution to forum users, ideally with the two sharing the same user database, or at least having duplicate user databases. (read: seamless integration)

Failing this I was thinking that a process could be automated to duplicate new user accounts into WordPress when they sign up on the VB installation but I'm not exactly sure how difficult a proposition duplicating the username/password would be. I'm not afraid of work, I do however want to know what I'm getting myself into here.

So I've got three questions for those of you who are familliar with both:

Is the time involved in getting WP to use VB's user database worth it, or would a scripted method of synchronizing the databases be better? Would password retrieval pose a problem?

How difficult would it be to modify the VB scripts that are responsible for creating/modifying user information to pass the relevent info to another script that would create/modify the accounts in WP?

Would it be better to use PHP or cookies and JS to securely pass login information between the two, so people will not need to log in twice?