Dehner's - in Omaha, Nebraska.
They actually made them at the time for the Army Officers from the Cavalry School and Horse Cavalry units - including Patton and Reagan...
They're expensive - custom made from 'your' foot measurements.
In more modern days, you've seen examples of their work if you've ever seen 'real' Tanker Boots.
I'm sure there's an outfit somewhere that's more reasonably priced, though.
Good Luck.
Vaya,
Scouts Out!