Robin Mather

It's similar to the belt drive thing... the Gates Carbon Drive looks like the solution. And it works with the CK hub and the 130mm BCD Truvativ cranks. Where it fails is the Rohloff hub. But I understand that Rohloff have that in the works too.

Yeah, cogs for 9 spline hubs and alfine/nexus 8-speed already available. Rohloff, Sram, NuVinci coming soon apparantly.
http://www.carbondrivesystems.com/forbikemakers.php?lang=us
Incidently my soon to arrive frame, has a 'keystone' joint at the drop-out to insert the belt.