My previous MH had a "PowerNow" 5500watt generator made by PowerTech for a couple of months probably as a test of the market. They'd taken a Kawasaki V-Twin engine, mounted it on rubber supports to a metal plate. On the other end of the plate was an Italian generator driven by a belt under the plate. Because the engine wasn't designed to be serviced from the side, I couldn't get at the rear sparkplug without pulling the generator out. Thankfully, the MH manufacturer used a heavy duty drawer slide but it was awfully tight pulling it out past the sidewall. I had to disconnect the exhaust to pull it out. The rubber supports compressed allowing the crankshaft to grind the bolt holding the pulley into the bottom of housing.
Overall, it had the power and the Kawasaki was a fine engine but it just wasn't designed for the application and was a pain to deal with. It had to come out to replace the air filter. PowerTech never sold all of them and while fussing about mine to a PowerTech rep at a couple of FMCA rallies, he offered to send me another. I never took him up on his offer because one was enough!
I pitched hissy fit to Onan about 3 years ago in Chandler, AZ at the rally about not modernizing their line up. I told them the time had come to switch over to inverter technology so I wouldn't need to put up with their constant speed models whose design probably dates back to the 1940 or before. The engineer I spoke with was on board and had me rant in front of his video camera about what I wanted to see and he completely agreed it was time for design changes. I'm still waiting. I can't figure out why no one has challenged Onan's share of the RV market by offering 4000 and 5500 watt inverter type generators. They could take over the market in short order. Like others, I bought a 2200 watt Ryobi inverter portable and set it next to my MH when boondocking. It sits out there and idles giving me all the power I need to charge my batteries and watch TV every evening. I shut it off when I go to bed after the blankets have warmed the bed to perfection. It uses about a gallon a day compared to 1/2 gallon an hour my noisy Onan uses. Somebody's missing a great opportunity here.