Many of the large bus-type RVs now come with 'residential refrigerators' and many have no propane at all...........they are all-electric.
Of course, when you weigh upwards of 40,000lb GVW, you can have 15KW on-board diesel generators, Aqua-Hot diesel fired hydronic heat/hot water systems, 900 amp/hour battery banks, twin 2000 watt inverters, and so on.
This segment of the RV industry is rapidly approaching the 'house-on wheels' concept visualized by some of the original RV developers 100 years ago.
But for practical purposes, considering weight and space limitations, the Danfoss compressor units afford the best mix of cost, size, performance and low energy consumption.
I might be experimenting with the conversion of my current Norcold unit in my Beaver Coach sooner than I planned, as it seems to not be operating properly. I'll be testing it this week and will start a new thread on the conversion if it happens before I depart for OR.