Looking outside my sometimes blinkered view, I was gazing at the Alltec Aqua 40 at Carpex. It's highest spec is 2x3stage vacs and 100psi. Quite adequate for most and the same as what I am using with my larger Pro Plus. But the lower capacity? Not a problem in reality. If you use 100 litres on a job, does it matter whether you fill up/empty the water once, twice or three times? Not really as you're still only going to fetch and carry the same amount in total. PLUS, the Aqua 40 is a lighter machine than most, and costs, from memory, about £1500.
Safe and happy cleaning:)
Ken