The Gun Counter

Once you one off this, would you then offer them as a production item for others?

I dunno about in the US but in the UK most industrial machine tools run on 440 volt 3 phase. If you have a source of 440 3 phase you can pick up machines for way less money than 240 single phase ones.

My mates wife works for a company that installs and maintains generators and are Detroit Diesel agents ( amongst other things, they are also retailers and manufacturers of parts for Allison transmissions ) Another mate of mine works there as a service engineer, specifically on gensets.
The kind of rig you are proposing is about the smallest thing they get involved with, but the knowledge is there for me to tap into if you want me to reach out and get some advice.

Seems like you're in an ideal region for a woodgas generator(at least for your stationary power rqmts).

I have a 25 hp diesel engine. It blades my road, lifts my forks, digs with my back hoe, shovels stuff with the bucket, lifts the tent and teepee poles up into the loft, mows brush, plows snow, trenches, takes the trash down to the road, helps exercise the black lab, tows the cannons, flatbed and log splitter plus a bunch off things I haven't thought of yet. It's in the tractor, which has a 2 speed PTO which does a bunch of other things I can't afford to do yet. But I will, some day. I have always thought that the PTO would run a whole lotta stuff when rigged up right, from generators, pumps, saws, compressors, welders and some of that old fashioned, off the grid stuff, like heavy machinery via an overhead, belt driven drive shaft. John Deere, Kioti, Kuboti, Mahindra, and the Chinese all make them and I have found mine to be very handy around this place.

I'd be rather amazed if you can build that for $5K - TMK, that's about what a good diesel engine runs at that size, if not more.

I think it would be pretty difficult to recover the expense and weight of the second engine, based on reduced fuel efficiency.

Based on what you describe, it seems like one of these Hollingsworth 15 kW generator trailers would work. If nothing else, you could buy a hopeless case and just use the trailer and enclosure for whatever you end up building. I remember the "hush kit" made them pretty quiet.

Oh, and plus one for building it to run on 480. Much smoother running, very clean, and you can, probably, get some industrial components pretty cheap.

The only kicker being I don't think anything below the industrial scale is built to run on it.