I would agree the size match up would be a problem too for a private match to occur. For example if I somehow magically talked my wife into it and the ladies wanted to see the men wrestle... I am a pretty big guy... wife is normal sized. So of our friends and aquaintances, I could think of half a dozen that would match up well with her, but none of their husbands would match up well with me. I am sure most of us would do a one sided match if it meant the ladies would go next.
However for a video company, I don't think that would be a problem. Just cast the right size actors and your on. I think your problem is you are looking at too small an audience. It is a subset of a subset of a subset. You are basically looking at a market made of couples where both partners are turned on seeing the opposite sex wrestle. Again, I would think Matrock could knock out one of these no problem. It may make sense for a video company to be the dominant player in this small niche than to try to rush in to be a "me too" player in the MvM or FvF markets.
Daniel never really got back to us what he was looking for, but if it was strictly the ladies fighting but some storyline about the couples, there was one called the "$600 wager" I think from California Wildcats back when they actually made catfight videos. If I remember right the storyline is the guys are bragging up their wives (who is the prettiest, who is the better in bed, etc.). Eventually one bets the other his wife could win a catfight. The wives then fight it out.