Maybe he meant a 6x6 in 35mm SLR style, like Pentax 67? This would be a Pentacon Six or Kiev 60 then.
Otherwise, Rollei and Hasselblad may just be fine ;-)
Hasselblad. Used equipment in good condition is readily available. Service is available. Sturdy, well built.
And if Heaven forbit, you ever want to cross over to the Dark Side, d----l backs are available.
And the prices on those digital backs are coming down on the used market. Used Imacon and Phase One backs can be had now in the $2,000 range. That's why I've kept my Hasselblad. I couldn't get enough for it to pay for a full frame Canon or Nikon at this point, so why not keep it and buy a back with an even bigger sensor for less money? Then I can put my superb Zeiss lenses to use well into the digital age.