We have no plans for any type of integration with other forum boards. This is simply because not everyone would be able to purchase a legit license (eg. vbulletin and ipb) to use with jolt.
Instead, we've created jWeb, which is a web integration software for your jolt server.
I don't think its fit to not allow forum integration because of legalities when you yourself "took" the css code for the Headlines theme from WooThemes (WordPress Theme supplier). Just countering your point :)
phpBB has a GNU license; I think JoltDev should be focusing more on forum integration for phpBB, as a better alternative than forum integration for forums that require purchased user licenses.