DON"T CALL THEM MODELS!!!
Ok, I recently came across a somewhat related topic on Fetlife.
Now: To the OP: if you are trying to find people for private sessions or, to a degree, a video collection only for your personal use, which is basically just a recorded memory of a session, DO NOT look on a modeling site. If someone is doing a private session with you, it isn't modeling.
Asking a professional model to do something like this will be taken as a huge insult 98% of the time, and could get you banned from model/photographer networking sites.
Try a dungeon, an escort, go to a foot party, maybe try Craigslist, since that seems to have a bit of everything, but please, please, PLEASE do not refer to ladies providing personal services as models. Escort or adult worker would be a much better term- even if these ladies also do modeling.
Remember this- coming from someone who does do fetish modeling- a model is there to BE and to portray a fantasy, NOT to fulfill it.