I think the word "suspension" is a bit misleading in this case. I suspect you will find it is actually only dampening of "trail chatter" and this is acheived through the flex of the quadrilateral that is the top tube, down tube, seat and chain stays. Normally these would be stiffened by the seat tube but because the top isn't fixed the quadrilateral will have flex in it.
I also think that pic is only a proto-type or "mock up". Have a look at the stays, all 4 of them have a small section of tube joined into them to lengthen the rear dropout from the bb.
It may well be legitimate but I would be wary about dropping coin on that until you found someone that has bought from that buyer.