I think so. Do you need one that big? You might want to look at portable lighting generators from the construction industry. They’re diesel, on wheels but…might not be easy to find any over 8kw? 🤷

 

A bit of a long shot but you can probably find a couple of inverter generators, set them up for parallel configuration to get you past 12kW then install NG conversion kits.

Two (2) Genmax 9000 inverter generators gets you around 18,000 peak Watts and 15,200 running Watts (50A hookup built-in)
Two (2) Predator 9500 inverter generators gets you around 19,000 peak Watts and 15,200 running Watts (50A hookup can be built on the parallel kit)

But those wattages are based on gasoline. After NG conversion, you'll likely still get a little over 12,000 running Watts.

 

Wen has a couple of high wattage inverters, but they are not parallel capable for some reason. For inverter power at wattages as high as you need, your options will be limited. Powerhorse makes a 7.5k/6.5k inverter that can parallel as well. On natural gas, you may not get quite up to 12kw though, but you should be able to get fairly close.

 

DuroMax makes a gasoline/propane inverter generator that puts out peak/run of 8550/7200 watts on propane. I’m not sure how well made that generator is, or what’s involved to transition to natural gas. It is parallel capable with a second unit.

 

Once you get up into that KW range, Cummins and Kohler NG standbys are your best bets...

 

None exist that I am aware of. Like the others have said, best to parallel two portable inverter generators together. For natural gas, you may need to install a conversion kit on each and you will likely get 10-20% less power output. I have the Honda EU7000is converted to run on natural gas and if I needed that much power, I'd either parallel a second one or go with a larger, water cooled standby unit like the Cummins RS25.

This guy has paralleled a few of the larger inverter generators, but none of them were converted for natural gas:

Maybe poke around his channel and see if there's any brand that has what you want and has a conversion kit available.