you can also use a quill to threadless adapter , then use a threadless stem .. which are more abundant , now.
there are 25.4. (inch) 26 and a oversize (1.25"), and shims machined to convert any of the larger sizes
back down to any of the smaller ones.
I've used Loc-Tite Red on shim interfaces
of course you can buy a lovely Nitto nickel plated lugged stem ,
and hire one made by anyof a number of custom frame builders.