I do have pictures of my current slipper setup. It actually uses a collar to hold on the spring, like the Dominator's slipper. I tighten the slipper by sticking it in the vice and put pressure on it by using a hand clamp. Here is a picture:
Just in case you are wondering, this is a custom mount (by me) for this setup that has a built-in motor mount (you can see the purple Feigao motor).
In regards to your questions/ideas,
I don't think that you could get the Maxx idler gear shaft to work properly in a 1/8 buggy with a typical diff setup. Maybe if you were to make a picture in paint to show what you mean, I might understand better. But you have to remember that whatever you do, you need to be able to attach the outputs for the dogbones to go into.