Hi

This is what I came up with. It is written in Python so you need to have it on your tablet.
You can load mp3 samples and play them.
Plays on button pressed stops on released.

Download here

Screenshot

Unzip it to your memory card
Run Utilities/Terminal
And in terminal run:

That is it
Remember to replace mmcX with proper card name (mmc1 or mmc2)

I know that the code is ugly, but it works for me