Saw one in Holmes County, Ohio that had a solar panel on it, and LED lights. Brake lights and turn signals are pretty common. Waiting to see one with lights on the horse's harness...
I used a similar (50 Cal) box on mine, but removed the SMV hardware, bolted the box sideways to its bracket, and remounted the SMV hardware to the outside of the box. Mine's gray to match the ROPS.
The old - not QH compatible - one is what I've got, too. Bit of a PITA, but usable.
The new WB 10/WB15 are QH compatible, but within the redesign the price went from under $300 to OVER $800!
My 'old style' ballast box is labelled "300# for BX; 400# for B.' I have about 300 pounds of gravel in mine. It's been adequate for anything I've used the loader for so far.
Mine was even simpler - the rubber grommet worked its way up out of the hole in the dash, letting the throttle lever move too easily. Pushed the grommet back in and the problem was solved.
Gotta ask now: If the deck has been on for over twenty years, has it ever been serviced? Gear oil changes, drive shaft U-joints and splines greased, etc. Surely you've had the deck off and on a number of times for that.
The 'regular cab' pickup is becoming a rarity, unless you want a stripper 'work truck,' and some brands aren't even making those. Seems like everybody is only making double cabs anymore. Even the extended cab models are getting rare.