Andi,
Don't go for a high top u can't get them under barriers or into a car wash stick to a low roof transit thats what I have.
Bane base unit 60 gal plastic tank which I had made to measure with a 3K immersion heater in the side to heat water overnight. Then I run it through an Ashby Steamate. Take the wheels and handles off as u can't use it as a portable anyway. Put a larger pulley wheel on the vac belt to give more airflow and u can get 250 psi out of the pump if u turn it up. Put a remote control on the plug and u can turn the machine on/off from wherever u r working.
Regards, Martin.