I have been toying with sounds and I have come up with a slide whistle / slide flute app!
It looks like this at the moment:
It has a range of two octaves, with the central frequency at 880Hz (A5) and goes from 440 (A4) to 1760Hz (A6), sliding up and down you change the pitch, and going left to right changes the volume, it works almost as a Theremin!
Now I have to do the "art" for the app and it will be ready to publish.
I'll keep you updated.