Distortion pedals tend to not reaaly be appropriate for circuitbending as they pretty much do what circuitbending does already. They also tend to be very simple circuits.
Of more use are cheap digital delay pedals where you can corrupt the sample memory, analogue delays where you can create feedback loops and distortions, and most modulation effects like phasers and flangers. The cheaper pedals like Arion, Danelectro and all those companies you've never heard of before tend to be more bendable in my experience. They also tend to have plastic cases which is a whole lot easier for mounting controls.
I'm told those cheap Behringer pedals can have some good stuff done to them but they do use tiny surface mount components and so are difficult to work with. I wouldn't recommend them to a novice circuitbender.
There some information on some pedals in the
Effects Units section of this forum
