I'm just gessstimating here but the tru=flow @ 60 psi, with a zero tip nozzle, at the end of 21' 1/2" PVC PIPE, MIGHT DO THE TRICK FOR YA ? GOOD LUCK

I can't give any advise on a power sprayer but you are correct about a trombone sprayer. I have a Hudson trombone and 20-25 feet is the best you can get out of it.

I have gas powered pressure washer 2650 psi and 25 gallon 12 volt sprayer hook to it as nurse tank just put male garden hose end on 12 volt sprayer hose. I can spray fall web worms out of pecan trees when wind calm it spray very high in morning when air is rising in afternoon late and night fallin I spray garden over top so whan spray stops it settle on plants I spray 4oo tomato plants from outside of rows across garden to. Getting back from plants about 10 feet works best so as not blow leaves off spay mix is about same as if do it just with 12 volt sprayer sometime even less to spray the time engery saved is amazing. I haul this setup around in back kawasaki mule but would work in cart if 4 feet square box are sled like good pallet with everything tied down. Spraying my peachtrees take 2 seconds per tree. I put 2x4 across bars on mule to rest wang as haveto hold it with left hand spraying fence rows around pasture.