CircuitBaker (on Tindie) has put together a control shield to make prototyping audio projects a bit easier.

This convenient shield includes 6 pots, 4 buttons, 4 LEDs, 4 mini jacks, and 2 SPDT switches for use with your audio project.  Just add a Teensy 3.x and Teensy Audio Shield (optional) and you are ready to go.

Code, schematic, design files, and bill of materials are published on GitHub.