I didn't read your posy word by word but I kind'o got an idea of what you're looking for.

I use the Peavey PC1600 for live gigging, it's really a great controller, it's sells used on Ebay anywhere from $150 to $250. but for what it does, it's worth every penny.

Anyway, the amount of controlling abilities of this thing is endless, and yes it has a built in Midi merger.

I hope that helped.