Multiple domains, different skins
 

I've been using IPB, though I'm considering a switch to vBulletin for my next website service.

Though the switch will have its own concerns, the primary on my mind is the use of one central login system and database for multiple URLs with also multiple skins. This way users can keep their profiles, but have choices as to which type of site they would visit from the start.

For example:

SITE 1 = Database A, URL A, Skin A
SITE 2 = Database A, URL B, Skin B
SITE 3 = Database A, URL C, Skin C

Thanks