I do not know of anyone but if there is any way for you to do it yourself, here is what I did. If you really want to give it a try, I can send you a wiring diagram as well.
I purchased this pure sine wave inverter that comes with the on/off remote switch and battery monitor.
https://www.amazon.com/gp/product/B07MTXZVBJ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1I also wired mine in with a relay to the generator breaker on the main power panel.
https://www.amazon.com/gp/product/B07FCJFGL9/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1This way when the generator is on - the relay automatically disconnects the inverter.
I also wired to the output of the inverter off this relay to additional small relays to turn off the battery chargers and the hot water heater automatically. This way you don't get a large load from the water heater and a never ending circle of current from the chargers trying to charge batteries from the batteries.
https://www.amazon.com/gp/product/B087G6D24G/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1You can get 2/0 cables from Harbor Freight already made.
https://www.harborfreight.com/3-ft-inverter-cable-set-20-awg-63748.htmlCame to about $400.00 w/ wiring and everything. Now I have whole boat Pure Sine Wave inverter system for TVs, Coffee, Blender, even microwave for a couple minutes.
I also have two solar panels on the hard top to keep everything charged during the day putting out 20 amps on a good sunny day.