Cell music composer

I'd like to see a cellphone app for arranging music, combining an MP3 player that gives control of what segment of a song to play, and a Lilypond or Finale-like musical notation input editor and synthesizer.

A cell phone piano could be part of it. Seven number buttons are used for the scale, two for accidentals, the remaining three for changing octaves or re-centering the scale on a certain key.