Hi Neon,
I have thought about the SRAM Dual Drive before, actually i really want to fit one to my motored bike because i never have a 1st gear that's low enough for the hills i need to climb and never have a gear high enough when selecting a front chainwheel that's low enough for hill climbing.
A SRAM Dual Drive is exactly the solution i want, save for a proper Rohloff hub that's awfully expensive.
My concern (and it may be unfounded concern) is that the planetary gear drive would blow itself to pieces with the torque put through it from a 9T to 44T Jackshaft ratio and a 30T to 36T chainwheel to cassette ratio.
If i could be reassured that the Dual Drive hub was sufficiently strong enough to cope with the torque applied to it, my bike would have one fitted tomorrow.
Fabian