I gotta say, if you want a wild handheld music making machine, look no further than the Polyend Tracker Mini. I don't know what the deal is with software updates, but the beta I have now has more of a toolbox than I could ever use, and the constraints are enough to give it its own flavor as a musical workstation.
Samples are a cajon, a shaker, and my voice. Song is called "In a Box"