There may be such an animal but it will cost you more than converting one end or the other to match. Although the 7 pin flat connector is not as good as the round ones (in my opinion) it is the almost universal one used on RV's today, and it is the one TV's come with when factory equipped. By converting your trailer end to a flat pin connector, you can tow it with virtually any other tow equipped vehicle.
If you go that route, look at the 7 wire flat pin connectors you can buy and pick one with brass pins, not silver looking ones. The brass pins clean better, and last longer than the plated steel ones that are also commonly available.
Also, if you do this, be careful of the color codes that are used. The older AS and Argosy's used a different color code from the ones used on flat pin connectors, so you can't just change it over wire for wire (flat pins are labeled with colors on the screw end connector).