I was going to suggest that you could take some mainstream stock shots prior to your (nude) model taking her clothes off, but then I realised that if you used it on a mainstream site some people may recognise her.
I wonder how often that crossover happens, without the mainstream side realising she's got her gear off elsewhere on the web?
I had some vague plans to shoot and sell stock photos a little while ago, but I think I'm better off just selling a limited set of scenic shots as prints to consumers, just something extra on the side...