I agree with previous comments that a truckmount does not need to be 3000 PSI, and the cost of that setup for something that you probably would never use is just a "mine is bigger than yours" syndrome.
If you want to pressure-wash, by a pressure washer setup.
Because I have a very hot 240,000 BTU LP heater tested to 5000 PSI in both of my truckmounts, I can use that if I pressure wash. I have washed houses (using a pressure washing gun assembly), decks, walls, patios, driveways, pool aprons, etc., using up to 1200 PSI and 300º heat at 4 GPM with a normal sized truckmount. It has gotten the job done every time very quickly with no blow out or peel damage.
With a reliable APO and a 65 gallon waste tank, I can clean (carpet, upholstery, tile) all day without stopping.
So I do not have the initial high cost of a BIG unit, a bigger, heavier truck, more fuel needed for the truck and machine, etc., I just have a well designed normal sized truckmount system humming along at 3000 RPM.