It's not a very innovative idea. Its just to make a board that makes it easy to connect your instruments. And instruments use big jacks and you want some real potmeters and foot switches. As simple as that.
I, Øyvind Mjanger, have build effects for a decade under the brand OnkartGromt. That should give me some background to hopefully make something that can be used on a stage with professional musicians.
Program your own...
So why not start to make your own effects? You got a Teensy, so why not get a proper board to hook it up to?