Go into a truck stop and you'll find lots of 12v stuff and yes, those TVs are pricy considering you can go into Best buy and get one that uses a brick much cheaper.
We have been collecting 12v gear since the 80s and I gotta tell you, most of it sucks. Most of it is smaller and slower than the 120v version and the cords/ plugs like on our 12v auto drip coffee maker is just not up to the job. I tested it once last year ring on the battery and the plug got so hot I couldn't hold it.
I did convert a 15 inch LCD TV/ DVD combo to 12v last year and it worked fine except the trailer has no 12v plugs. I used a 35ah gel cell to power it and that doesn't last long enough on a cold rainy day.
Next year it will just be easier to do a 180 and put a big PSW inverter on a big bank with it's own solar system, plug the trailer in and use 120v gear.