My LBS has a Polyvalent (650B specific frame) right now. He's a VO Imports dealer. The TT is horizontal from all I can tell and I've looked at it a lot.

On first glance they don't look particularly special or "worth the money" when compared to a nice 80s Japanese frame, but you're not going to find a used one with all of the braze-ons, extended head tube and specific geometry that the VO frames offer. These frames were built for a relatively narrow/small market.

That said, I enjoy "re-purposing" older frames and that's why the few bikes I've built up have been about as old as I am.