Thanks for the suggestions. I'll be looking into this more quite soon. But I can't let myself get too many simultaneous development projects going on! Believe me, I can really get carried away!
Donations aren't something to count on, but if you could produce a web version either as your primary, or as a demonstration that could get whatever site you put it on quite a bit of traffic. Traffic brings its own problems though. A charge of a bitcent, bitnickle, or bitdime to unlock some of the advanced functionality though might bring in more revenue than a higher charge or suggested donation. If we've learned anything from mobile app land, lots of small purchases make more money than a few big ones in a lot of cases.
If you worry about getting carried away just remember that it is okay to let dead end projects die. It is alright to start a bunch of small projects to learn aspects of how bitcoin works and then kill the small ones to focus on a few you find interesting or potentially lucrative. Rather than trying to make a single big project at the outset instead make features that let you learn and practice, which might be useful incorporated into a project.