http://ultradevi.tumblr.com/post/114773408267/justine-here-ive-seen-other-for-mistress There's this Tumblr called "for your use, Mistress"... it's done by a middle-aged guy who really likes to be dominated by a woman -- but, being a hip* person, he also offers photos of girls serving THEIR mistresses. The above URL is one of them.
Also on the site is a shot of a sweet girl, not a domme nor a subbie, as far as I can see (well, black panties do not a domme make, but who knows?) --
http://ultradevi.tumblr.com/post/114776783262/justine-here-ooh-shes-very-pretty-but-not While wandering further on "for your..." I just encountered another delicious shot, which certainly could be a girl with a mistress (she'd be driving) --
http://fantasticfetish.tumblr.com/image/114758186272 ______________
* How do I know he's hip? For one thing, he titles his queries tab: "Ask me anything, so long as it does not degrade Women." (He has that thing about capital-letter in referring to one's domme, which I think is a bit silly.)