mod volume pedal to feedback looper

[cnspedalbuilder]

Hi, so far, I mainly build circuits from layouts or pcbs, but have not done substantial mods to an existing pedal, so forgive me if this is a dumb question.

I wanted to build a simple feedback looper like the Beavis Audio pedal:
http://diyshoegazer.tumblr.com/post/3042080186/diy-guide-to-feedback-loop-pedals


I was thinking that it would be cool if you could control the feedback pot with an expression pedal, and it occurred to me that you could mod a cheapo stereo volume pedal into a feedback looper. Has anyone tried this?