I think zerobug is talking threadless. he's got a threadless 1" steerer tube and wants to use a 1 1/8" stem with shim (with an OS handlebar clamp).
I also have a 1" threadless stem, and want to get one with more drop, but it's tough to find 1" threadless stems (with a lot of drop). I think the shims work fine, but have no experience with them.