I'm also interested in rockbox for smartwatch. In this case, yes, I think an app would be the best way to go since I still want the watch to be able to function as a GPS running watch. I'm specifically interested in the Garmin GPS music watches. They "hold 500 [or 1000 depending on model] songs", so have some amount of internal memory. I'm interested in audiobooks and most audiobook players blow, especially when you are trying to shoehorn a music player into working with audiobooks. I love that Rockbox has all my features covered, ability to play at different speeds without sounding like a chipmunk, skip back or forward in short hops, and just generally being flexible to work how I want it to rather than how most people want it to. I really hope you'll consider adding an app at some point.