I think I know what you mean. I saw a gardener/landscaper type guy using one round my way not long before Xmas.
I'm guessing the engine and pump are only small though because I saw a guy at around 4 o'clock time and he had only just finished cleaning about 100m2 of block paving as the sun was setting. Although I have no idea what time he started, may not have been til late
I don't know how he set up, ie direct hosepipe feed or tank, I should have pulled over and said hello.