LONG ANSWER: (Short answer below)
Actually the under development code (not version 1.0.2) basically supports a "plugin" type system where all of the forum specific code goes into one specific file. There is not currently an option to choose which plugin to use and phpBB is hardcoded at the moment. I passed (now an older version) or the under development code to Wolverine who is working on an SMF bridge. My hope was to get him to adopt our plugin approach and get him to do at least the first pass of coding for SMF. But even if he doesn't do that we would code it up eventually...
Plans are also on the table to support phpBB Component...
But before Martijn or myself add either we want to mature up the features of the plugin... I have spent a good deal of time making sure all forum specific code was in a seperate php file (and class) and added a simplified plugin architecture.
Recently I have been polishing up the User Profile Tab making it look more like that of the SB plugin with subscriptions and posts (pagination and sorting)... In the development code those features are there just need to tighten up subscriptions so that only the actual user can see them... and then hook up the "unsubscribe" links... pagination, etc. with the posts is implemented... not sure I understand the search feature that they put in though...
Even toying with adding xAjax into the plugin to do some immediate feedback stuff like unsubscribe (then update list) or for import/export or users...
SHORT ANSWER:
Yes we will extend out connector to cover multiple forums. Currently SMF, phpBB Component, and of course phpBB will be included... I have even thought about making it work with SB and maybe replace the CB forum plugin... not talked with Beat or anyone about that though so that is just speculation.
If you have any other feature requests then log them on our tracker at
developer.joomla.org/sf/projects/phpbb_connector
Starting to get more good ideas for feature requests.