This probably belongs in the Build it Yourself section, apologies up front.
You can build your own "custom" sprayer, pretty easily.
I built a 55 gal 3 Pt. sprayer using a plastic CarWash Barrel. Mounted vertically on an "L" shaped 3 Pt. frame. 50 gals of H2o at 8 lbs per gallon = 400 lbs. Can also be used as a Ballast box.
The Barrel is conveniently marked for every 5 gallons down the side.
Used a 12 volt ShurFlo RV water pump, wired a removeable plug-in cord, with On/Off that can be switched from driver seat. You can spray a straight row, switch it OFF, turn around, then back ON for the next pass.
Got the boom portions from Northern Hydraulics (now Northern Tools?)
Sprayer Boom Kits | Sprayers | Grounds Maintenance | Northern Tool + Equipment
Booms folds up for storage. I hooked it up so that each boom (left and right) have their own ball valve...so...you can run only one side, if needed, leaving the other folded in the upright position if in a tight spot.
I had a strip along my driveway that only needed one side spraying.
Mounted the RV Pump into the top of the drum using SS screws, placed a pvc dip tube down to near bottom. installed a small screen filter up top, at input to 12v RV pump. Use the existing bung for filling.
Drilled and tapped a drain plug at bottom for rinsing.
Later I plumbed another ball valve on the output side, and installed a spot sprayer nozzle on a 20 foot piece of garden hose.
Works like a champ. Saved $$ building it, no regrets.