When I first got my first Turbo Duo, the local Radio Shack(only place in town to ever carry 'Duo' stuff) didn't have the Duo cable, but they did have the Turbo to Duo adaptor.
So for a while, I was using my Turbo cable and Turbo Pads/Tap exclusively on my Turbo Duo. I lost the Duo cable I eventually got in one of my moves and replaced it with one of those computer cables(Apple keyboard?).
I have the wireless PCE pad set, but it's only good for RPG's since you need a clear path between the receiver and the pad. So I usually just use the non-official extension cable and whatever Duo/PCE pad I find lying around.
I do give the cable coming out of any PCE system some length on the same surface the system is on, sometimes with something weighting the cable down, to avoid wrenching the cortroller port out of place(I wish the Turbo - Duo adaptor cord was longer). One of my systems has a touchy port now, and I assume its from getting jerked around.
I had a white PCE system with a nice little A/V mod whose controller port got wrecked to the point where either only one direction worked, or all but one direction worked. I wound up selling it as-is.