Ok, so here's the scoop. Currently importers are a pretty big pain in the rear. Each has to be completely written from scratch. They are also very hard to maintain every time we do database alterations.
What I plan to do is write some sort of core code that can be used for all importers and then for each forum we want to bring in, we just need to write a much smaller portion of code.
I have 1 person that has offered to tackle this actually, but need to see if they really want to do it as it's a pretty big job. Otherwise, this will probably have to wait until we're done with v8.