The "Surface Table" by John Barnard and Terence Woodgate is three-meters long — and just two-millimeters thick, due to its construction from carbon fiber.
There's one tiny discrepancy in the description that gives me pause: Stylepark describes the table as "just 2mm at the edge", which implies that it might be thicker elsewhere. But probably not!
I would love to play around with one of these. I suspect they're still relatively fragile — no sitting! — but you could probably pick them up and move them around without issue.
Price: unknown, but surely a heap of Euro.