Well, at least in your Photo Shop example, you have a removable face plate on the bar clamp..
so the quill wedge bolt could in theory be tightened first ,
then the bar clamp re assembled around the handlebar.

You would need to build an assembly Jig first to hold the parts in allignment,
that being done , the actual welding could even be automated to make thousands of them.




note : Thor Who posts in folding bikes thread , because he sells them,
has an adjustable stem accessory [made by TW's Zoom company]
2 1 inch clamps, double ended, and a piece a to replace the handlebar with a short plug.

the "aberhallo" can be adjusted and be above , and a bit behind the bar clamp in the original stem,
so would shorten that already short stem .. ..[in #2]

just saying ..