I note that there hasn't been much new activity here, which is a pity. This is a great subject.

A comment on resources:
I recently responded to a newspaper ad about a "Presentation on MIDI," and found that the presentation was by a church organ manufacturer.
Attendees were a group of phenomenally talented and very professional musicians, all of whom where using MIDI in their church music programs. (Although some of them didn't know that's what it was how it worked.)
Apparently, MIDI sequencers and sound samplers are the "guts" of the newer breed of "electronic" organs.
For those who have an appropriate 'contact,' this might be a place to go to find advice, or to get your hands on a piece of good MIDI equipment.

Based on comments from the people at that meeting, there are probably a lot of churches with some good equipment that they don't know much about using, so if you find this is the situation, you might be able to help them too.

John