Let's talk about quill stems that fully open, either a hinged clamp or a removable clamp. Criteria: that don't look awful.
I think 3T kept trying to make graceful quill stems that had open faces. The Motus, Evol, Mutant, and maybe others. Cinelli made the Oyster; also the open face Frog, but it fails the "awfulness" criteria IMHO. Mavic made the 370 stem with a notched clamp that lifted off, I've never seen one in the flesh. What are some others? These were all pretty unsuccessful. Any thoughts on why? Maybe there just isn't a need.
Yeah they sucked too. They were ugly and prone to failure. There are still lots of cheeps stems out there for quill with removable plates but they are ugly. The threadless stem was a great innovation. I can't stress enough how superior this is in terms of weight savings and ease of maintenance. Think of the bike fitters changing stems out on floor bike etc... and what a PITA it would be if they were quill stems with a single pinch bolt. Scratched bars and re-taping all the time. It sucked.
Quill stems went through all the evolution, removable face plates, 1-1/8", 1-1/4", alloy binders and wedges, they were incredibly light too, but ultimately the threadless system is better. We're seeing threads disappear on other areas of the bikes too. BB's gone. Axles, reduced... Now it is just the oversized QR axle that has threading on the end and the hubs have no threading left at all.
Quill stems are beautiful but would not fit on anything made today. Thankfully we are seeing a resurgence of classic components following the resurgence of classic frames and a few have been posted. I like the new thread less stems that have an extension to do away with the spacers. Those look pretty good IMHO. but I also think a modern bike with threadless and no spacers on top still looks good.
store.velo-orange.com/index.php/components/stems/threadless-stems/vo-tall-stack-threadless-stem-31-8-rise.html
there are also fancy steel type of stems like this I believe.