MOTM

Thought about it some more, and my current "need" is...

a 1U module with 
1) one (switching) (un)balanced 1/4" in
2) one (switching) (un)balanced 1/4" out
3) some trim controls
4) a switch to control whether the input is pulled up from line level, instrument, or mic, 
5) a switch for phantom power 
6) a switch for hiZ/loZ
7) and a decent level meter (both ways)

OK, that's not going to fit well in 1U, so you can skip the mic-related controls to make room for level meters.  Throw that stuff on your triple-preamp.

It's basic, but what more do you (er, I) need?