It seems that MIDI is the new hotness for iOS music apps. Every week brings more apps adding MIDI features. Among the best so far are Bassline, Modrum and Funkbox, all of which have implemented MIDI Sync and local Network midi. This allows for cool stuff like this.
Looks like more big names are getting in the game when it comes to MIDI peripherals. We already have stuff from Line6 and Alesis. Yamaha has also announced the i-MX1 which looks a lot like the Line6 Midi Mobilizer but supports CoreMIDI. Still waiting to hear what the price will be.
All the attention that MIDI is getting validates my decision to work on developing a MIDI sequencer app. I expect to post some more info on it within the next month; all major features have been implemented and I am currently working on implementing the final interface designs. MIDI updates are coming for bleep!BOX and bleep!Synth too, most likely after the launch of the sequencer app.