The site you referenced is not one specific breeder's site--it is advertising for several breeders working with various breeds of dogs. I particularly found it humerous that they made a point to to say that they produce quality "hybrid dogs...not mutts".
Sorry, but I crack up anytime anyone refers to their dog as a "hybrid"--I mean really, who are you trying to fool.
In any event, you already have your doubts about the site. That should tell you something--follow your gut. IMO, there is no reason to take a chance on a site/breeder you are doubtful of when there are reputable breeders out there you could turn to instead.