There is an amazing young girl who teachers clases at Core Studio who does exactly what you are asking, give them a call, sorry can't remember her name. But they do hire the trainers out.
HTH
I'm looking for someone who could teach a group of 13 year old boys and girls some hip hop/street dancing (or any cool kind of dancing!) at my daughter's birthday party. Anybody know of somebody who does that kind of thing? Thanks