I've set up a Tindie store as an experiment. Perhaps some of the little widgets I build to solve my own problems will also help solve some of yours!
One product so far, a keypad-to-serial interface gadget. This isn't the first such gadget, but it's the only one I've seen with its feature set. For example, It will interactively figure out the wiring of your keypad for you -- you just need a terminal app.
Plus, the manual has dinosaurs.