Here is a tutorial on how to get started with mSequencer (MIDI Pattern Sequencer). In this video I use mSequencer to control all 8 channels of Korg's iPolySix via virtual midi. This video doesn't even begin to touch what a great app this is. If there is interest in it, I will definitely be making more videos on some of the more advanced procedures you can use as well as a lot of other options I couldn't get to in this video.
I highly recommend using an external midi controller with this app to build your sequences.
Conclusion: This is an excellent app for anyone wanting to program midi sequences and send them to apps via virtual midi. It gives you a larger range of control then any other sequencer app I have ever used. This app does not support Audiobus but it definitely should. Well worth it's price.
KORG iPolysix for iPad
Developer: KORG INC.