http://www.sonuus.com/products_wahoo.html
this bad boy's got it... and a loooot more.... far and away #1 "wah" device ever made in my humble opinion, yet very reasonably priced
Or, you could put your wah in a blender/looper pedal with something like a One Control Mosquite blender! I have my envelope filter into a tweedy overdrive in my Mosquite loop. Its awesome dialing in a bit of clean with envelope filters!