There is that Aleph Bees device. Granted, it’s a lot of programming and menu diving, but for the code writing kind of person, it might be interesting. I believe you can program it to be whatever you want (synth, drum machine, sampler, effect unit), but I really don’t understand how!
“simply put, aleph is a small audio input/output device with a screen, bank of buttons, and series of encoders/knobs. it has the ability to host and run a variety of programs created by both monome and the user based community surrounding. new applications will be developed, documented and shared over time. elaborate mappings can be created without writing code by way of an easy menu driven environment and a thorough preset system.”
http://monome.org/aleph-detail/