Boy, can I relate to your issues. Big time. I had a vB 3.x forum.
I was waiting for a long time for the holy grail of vB4 to come out. I was waiting and waiting and so looking forward to a built-in CMS. The site that I have my much loved forum on is on an ancient html infrastructure and in dire need of a CMS.
I'm a die-hard Joomla fan and all of my sites are now built on that. But that html site was built before I discovered Joomla (actually in the Mambo days).
So, vB4 finally comes out and was a supreme disappointment. Huge. Then I started looking for alternatives. There weren't any that could handle my forum with all the add-ons AND the photo integration AND do anything to help with either a Joomla integration or Joomla replacement.
I continued waiting and hoping and investigating and still nothing was really going to do the trick.
Just recently, I FINALLY decided to just bite the bullet and do the dang vB4 upgrade. One of my issues was that there just were NOT any templates out there that didn't look like a vB4 forum. I do not like the look at all. I stumbled across a template vendor who had a look that I really liked a lot and that helped.
I've lost a little bit of functionality after the upgrade, but most is okay. I've still got some fine-tuning to do on my template, but it's pretty decent. I'm looking forward to PP8. I'm waiting to fine-tune the PP integration and look until I get that upgrade done.
After I get PP8 installed, then I will work on getting a Joomla template tweaked to get as close as possible in look to my forum template. And also hope that jFusion will work well enough to do user single-sign on. I've already done the Joomla migration from the html, but have not made it live yet.
You can see my forum here: Guinea Pig Cages, Care, Store, Photos of Guinea Pigs and More Forum!
If you figure out any magic of Joomla integration, please let me know!! I will absolutely be doing the Joomla/vB4/PP8 combination on this site.
I was going to go with a Joomla version of forum and users instead, but JomSocial and Kunena cannot handle the same functionality that we have with vB4 and PP. Nor is there any photo gallery software out there for Joomla that will work (IMO). I think I've tried them all on various sites.