newb questions about Tim Escobedo's Phuncgnosis

[avernalshade]

Hi I am new to both this forum and to building stompboxes, and have some questions about the Phuncgnosis.  I recently built one, and it sounds great, but I have some ideas of how I could make it better, and was wondering if they would be possible.  I like the way it sounds now, with one wah sound every time I play a note, but I also want to be able to play with the wah modulation running independent of my playing.  Since I don't own a drum machine or anything else that I could use to run the aux input, I was thinking that I could build some sort of improv metronome, with a decaying beep, and use that to run the aux in.  I could probably house it in the same box, and use an SPDT switch to change between the metronome and main input.  Naturally I would want to be able to control the tempo of the metronome with either a pot or some other device.  So here are my questions:
Is this possible to do, and has it been done before?
Will it be hard to build compared to, say, the Phuncgnosis?
Are there schematics for a suitable metronome available?

Thanks, and also props to Tim for some great schematics (I also built a Jawari, and it's pretty sweet too.)