All of my bikes with the threaded/threadless adapters have a single headset spacer in there. There are quill stems with removeable face plates, but they are far and few between. I can think of 3T mutant, 3T motus, Cinelli Frog, Cinelli Oyster, Salsa S.U.L. (most of which are recalled), and some basic profile/dimension/zoom ones. Only some of the basic profile/dimension/zoom and the Salsa are still made today that I know of. Yes, you can get others on ebay still new, but needing to get different lengths to find the right one can end up very expensive. I have been able to find a lot of threadless stems with 25.4, 26.0, or 31.8 clamp size relatively easily and cheaply.

I can get the bars higher without having to resort to a Technomic that doesn't have a removeable face plate with the threadless adapters. Each one with it flipped up is a normal 6 degree stem. The Cannondale is a 6 degree stem flipped down. I often change up bars on many of my bikes depending on what I am using it for. Most of the change up is on the track bikes which all but one are 1" threaded. I have track drops on a quill stem for actual track use, and a threadless stem with bullhorns or risers for street use of the same bike (with different gearing though).