My recommendation would be to close the forum over a long weekend, do your migration, then reopen shop on the new forum...
As for features you need, best bet would be to file a feature request over at ubbcentral; Rick is working on v8 afterall, best time to post requests would be now...
i've worked on migrating a copy of my forum over to vb, with two of the vb staff running most of the conversion and no one ever completed the migration. they gave up before i did.
