I've been poking away at it, but so far I don't think Midi Designer Pro 2 is what I have been looking for. I'm realizing that I'm basically trying to replicate the environment I had in Windows with Ableton Live. I want something like a vst hosting environment and maybe iOS isn't capable of this (yet?).
So if I were to add to my requirements, I'd like to be able to turn on the app (such as MDP2) and have it "call" iGrand Piano, iLectric Piano, Galilleo Organ, etc. at will when I hit a button. It seems to me now that I need a multitasking environment and iPads may not handle that well? I'm under the impression that I will need to set up the midi receive channel for each instrument app (and make sure they are set to run in the background), and open them individually along with MDP2. Then MDP2 may allow me to control in real time certain parameters, but there's still a lot of setup required each time I want to have a performance session.
Does that sound right or am I missing something?