Chris
Nick
On my Sam I currently have Shimano's 11 speed SLX mountain cassette (11-40) and derailleur with a single ring up front. I use Microshift's bar-end shifter made especially for them, since Shimano doesn't make a drop bar shifter for that derailleur. This is the same shifter Gevenalle uses on some of their brake levers.
Though it's 11 speed, as mentioned, it fits on an 8-10 speed hub, since the largest gears can fit out over the lip of the hub on the spoke side.
As a side note, I use mine in friction mode...feels much better than indexed, and I've never had problems finding a gear.