I had a mooch around on a Nucleon TFR with the gearbox. Good fun, but heavy and bloody expensive. I'm not sure the gearbox designs are quite "there" yet. A recent test I read concluded the Orange Patriot 7" was the better choice - and a LOT cheaper.

There's a very interesting Honda bike designed for their DH team - massive R&D costs, looks fantastic, wont be going into production though.

Isaac - regards Ti on a full suss - dont overlook that the custom drawn tubes and careful butting Litespeed implement look to create greater rigidity where it is required. I didnt find the Niota "flexy", but it is a great ride, very light as a basis for a bike and will last forever.