Well, The Great Work and KnyttWaDF will be the next installment in the Knytt series. I still have the idea that sometime in the future I want to make a new Knytt Stories that have a similar level format (or well, the level format won't be identical, but it should be able to import Knytt Stories levels and convert it to the new format), but can be fully scripted 'n lots of cool stuff.
Then, of course, I have lots of other ideas too. This one will probably never happen, because I don't know which ideas I'll end up make games out of, and I'm not going to think too much about it right now anyway since my focus for the time being is KnyttWaDF.