iPhone MIDI Sequencer / Clip Launcher

[WXLF]

Can anyone tell me if this type of sequencer exists for iPhone:

Must-Have:

-Clip Launcher & step sequencer

-Each clip can have an independent number of steps for odd time signatures

-Export MIDI

Would be nice to have but not necessary:

-Import Custom Samples with ADSR Envelope

-AU3 Hosting

-grid can be set to triplets, 5t, 7t

-Ableton Link Support

The app i'm describing already exists for iPad, but unfortunately it's not available on the iPhone. It's called "modstep", so if you are familiar with that, that is what i'm looking for. Also I think beatmaker 3 for iPad comes close, but i'm not sure if the number of steps are locked or not. Auxy would be decent but I believe it's limited to 4/4 common time. And the same with Garageband's Live Loops section with a locked number of steps for each clip.