Well, it certainly would be possible to do this, with a bit of hacking. You'd just have to add some new task to the main program that builds a dynamic front page and outputs it directly. Using the templating code and the fact that each thread contains a section with metadata at the top where you could stuff your categories and such, it should be straightforward enough.

However, it may be that you'd run into performance issues if you used this on a site with lots of visitors. It might need some sort of caching system, which would be a lot hairier to get right...