Novation released a free Max for Live patch which turns the Launchpad into a melodic step sequencer.

Simply connect the Launchpad to Live and then press “User 2” on the unit to connect to the Max patch. The buttons on the right hand side will control (from the top): velocity, degree of scale, octave, duration and the probability fo the step occurring. Requires: Ableton Live 8.1, Max for Live

Download the free patch.