Chris,
I'd like to know the same thing.
I don't know of any current plans available but if I were to cook something up myself
I'd consider using an Arduino.
This requires programming in C. and building some electronic interface to match the signal levels.
If someone else has already done it I'd rather not reinvent the wheel.
Others on here are way more qualified to answer this than I.
This is something I might attempt down the road but not in the near term.
-Steve