There is a "snip the tip" mod kit available for Dometic refrigerators that eliminates the thermistor and replaces it with a "rotary thumb dial" type of thermostat. I have no experience with it, have never used (or even seen) one and I don't know if it is a waste of time and money or a step up in refrigerator control.... Anyway, I'm not sure what the OP is asking, but I think it's whether there is a way to exchange his "no rotary thermostat" LP/electric Dometic refrigerator for one like in his home that has a compressor and rotary thermostat. If that's what he's asking, it's possible, but with it comes a lot of limitations on travel/dry camping. If those limitations don't matter, it's a matter of finding a refrigerator that "fits the hole", sealing the outside wall/roof vents and installing the new one.
If, on the other hand, he's asking, "is there a rotary thermostat that would better control my original Dometic refrigerator", then this link might be one solution:
http://www.snip-the-tip.com/cgi-bin/articca.cgi