"Mistress is out" ... "Mistress is in" ... pretty clever!!! I would definitely want to see something else as backdrop, but I like the concept. Also in this image I would light a bit the top part of the riding crop. Cool stuff.
I would've thrown a gridded light on the top of the riding crop so you can separate from the background. Also a reflector camera right to throw some light under her hat on her face would've been nice.
Interesting idea...however, the face looks a bit pasted-on. It is at an odd angle and the skin is such a different color than the shoulders/back as to make it look like it doesn't belong.