I have an old Danelectro Daddy-O which is basically a bad clone of a Marshall Guv'nor.
I've been slowly modding and improving it by replacing components with better quality ones and I've even drilled a couple of extra holes for toggle switches for diode selection and such.
It uses a momentary switch and what I believe is a flip-flop circuit or something similar. It has a terrible "tone-suck" when disengaged and I've wanted to change it to true bypass for a long time.
I was going to attempt this;
http://www.strat-talk.com/forum/effect-effect/142965-danelectro-daddy-o-revisited.htmlBut I wonder if this relay circuit might be an option...