Obviously, a wall mounted machine machine needs to have strong mounting or it will likely fall and may damage things in the process, so that's why we built strong steel mountings inside the wall for ours. A laundry machine also needs sufficient power supply and water (we've usually got plenty of both)
The idea for one of these washing machines came to us in Brazil (when we were driving our other motorhome, Blac, around that continent). At a campsite we met a Brazilian couple in a rather large bus-motorhome that proudly showed us their small front loading machine mounted in their 'garage space'. We loved it, it took up no more room than a spare tyre and gave such convenience!
We soon found out that these machines were easy to get in Brazil. There they seemed to be available wherever you might expect to buy a laundry machine; in Brazil people put them in apartments. In Australia these machines weren't generally available so we bought our Daewoo mini drum machine on eBay from South Korea. Amazingly, it arrived in less than a week after I'd ordered and paid for it.
Friends in Germany were able to buy one locally and friends in Switzerland bought theirs online too.
Ours, being from Korea, has the operating instructions in Korean but they sent replacement stickers in English with the machine and emailed me an English version of the manual.
We love having our own laundry machine. Without it we'd be paying for nights at campsites and coin feeding machines while there, or lingering in towns to use a laundromat. Also, ask all those travellers roaming around with 2 spare tyres if they've ever needed 2 spares.... if you do you'll probably come to the same conclusion as us: a washing machine is a better thing to carry, it even means you can carry less clothes!