Good stuff fellas, interesting to see other peoples setups. I made my seat from scratch with the intent that it wouldn't need anything other than some pipe insulation or bicycle inner-tube to damp it. Its secured by a form fitting shape all the way around the main frame, with the cowl at the rear hugging around the stock raised seat mount. The whole thing slips on and off pretty easily, just pull up from the rear and then from the front.
You can check it out in my Big Arse Build thread.
Cheers, and good luck - boingk