Green Ringer (another question today hum!)

[solarplexus]

Ok got another question...

I was wondering if the Green Ringer from GGG could be modded to have an expression pedal to play with the octaves (or frequencies) to make it sound like the ring modulator in the old BOSS ME-33 or the BOSS GT-6.  This was one of my favorite effects because I like wacky sounds, sounds almost like a chainsaw with distortion.  If it is possible to do such a mod, where should I start?