It would take a lot of coding to set it up with the proper header/footer (based on the templates, breadcrumbs probably being hardest). Your best bet is to integrate coppermine into it, theres a hack to do it here:
https://vborg.vbsupport.ru/showthread.php?t=62778.
If that doesn't work, you could hardcode the header/footer (won't change when templates do), and just do it that way. (Won't be vBulletin-based though (you lose the permissions, and all that).