I'm in the same boat, with just a little less reading. :)
It seems to be that if we want to encourage participation in GHC development, the first step is to lower the barrier of entry.
One way to do that would be to have a page (wiki, perhaps) that has a reading list for learning about GHC. I'd guess that there are a lot of people like Janek and myself who want to contribute, even a little, and just aren't sure about where to start. We're happy to do our homework, but we need some assignments, so to speak.
Another idea is to have a list of open tasks grouped by how difficult they will be and how much knowledge of Haskell and GHC will be required. This is somewhat at odds with the earlier suggestion to have domains in codebase, with separate de facto maintainers for each. However, it would make it easier for others to contribute. I could also see where the domain maintainers could put simpler tasks into a global index. That might mix the best of both.
I'll be happy to start accumulating information for the wiki page. I'm in the middle of drafting a book, however, so it'll be Feb at the earliest before I can really pay significant attention to it.
Best,
Eric