Just a preliminary investigation here but if you were me, supporting various JD generator engines which company would you go to? Papé, the construction and forestry dealer, who is a giant corporation covering the entire West, and has one nearby location in a large city? Or Valley Truck and Tractor, the ag/turf dealer, who is headquartered nearby but much smaller. I don't know how industrial engines fits into JD's support network. The stuff I work on is usually the sub 9 liter range.
Our AG dealer in Joplin doesn't carry much for parts or expertise for Deere industrial/stationary engines. We have several drill rigs with them. Even the yellow iron dealer in tulsa isn't great but better. I'm not sure which of the two would be best, the AG might be if there are a lot of engines in use for irrigation. Something simple like the Deere electric fuel pump on a Watson isn't stocked at either place. Maybe start with common parts you use and see who has more of them and that might possibly tell you who deals in more of them?
Western Power? Of course no need to limit yourself, if you need parts or whatnot any color or flavor of Deere dealer will usually be helpful. Western Power I believe is the Industrial engine distributor though.
I'd ask Deere directly, what their industrial supply is, for the engines in question. (scratch that, Western Power look like it... duh, on my part)
Did not even know they existed, I know there is a reason I ask questions on this site. Thanks.
PAPE