That's a good question.... I don't think there would be much profit in manufacturing new 126mm hubs for a very small market segment.
EDIT: I stand corrected - Phil Wood, as linked above.
But - vintage hubs in great condition can be found everywhere - most bikes were ridden very lightly after purchase, and have spent most of their lives hanging in garages like bats in a cave. You can find a great deal on a second set of wheels with great hubs without much effort. I've probably got 3-4 vintage wheel sets hanging in my garage, just like most folks in this forum.
"Love is not the dying moan of a distant violin, itís the triumphant twang of a bedspring."
S. J. Perelman