Last the more unusual equipment
I've seen similar vehicles in the Pacific North West where they are known as Skidgines (Skidder / Engine) being based on old logging equipment. This one was built on an old military tractor and was locally known as a soft track. It has a 200 gallon tank and 85 gpm pump which makes it a tracked type 6 engine.
Southern Florida has a fairly unique piece of equipment, the Swamp Buggy. Most used the mechanicals from a Chevy S-10 (engines, transmissions etc) and tractor wheels / tires. I think this is what you get if a monster truck and a party barge have a baby.
Sort of a hybrid transporter / engine, this one could easily carry 6 firefighters and had an 80 gallon tank in the "floor", it used a small electric pump with garden hose.
A smaller buggy used by Law Enforcement
More of a suppression unit, this one had a 200 gallon tank and an 85gpm pump under the floor (pump inside the screened area at the back). Only 2 seats but can easily carry 2 or 3 additional firefighters sitting on the tool boxes.
Similar buggy with a 3rd seat in the back and the pump mounted on the side
Transport only, it has seats for 6, but can easily carry 8 or 9 if needed. No water or pump on this one.
I do have additional detail photos of many of these vehicles if anyone decides to build one.