Mark,
I have never seen this machine before, but how about some speculation from an engineer?
The modularity is interesting, I would sugest that the layout is:
Top module - contains a single vac unit and possibly the pump.
Middle module - waste tank.
Lower module - solution tank, possibly with a compartment housing the pump.
The solution hose looks to be low-pressure - I would hazard a guess that the pump is 60psi ( no technical reason why it could not be higher, but if I am right about the vac, unlikely)
The power wand looks to have the 'normal' tip & wheel-forward, lift &-pull-back modes and the name sugests a vibrating brush. The length of the housing sugests that the motor is rear-mounted, with a link-bar running along the top at one side.
Go on mark, buy the thing and see how right (or wrong) I am
John.