This is commonly done when custom race cars of various types are
constructed.
There are companies which can do it for you.  Shortening the axle tubes is
not
so hard.  Shortening the axles themselves requires some special effort.

Its very commonplace when working with cars from the muscle-car era.
There are two common reasons- 1) using a heavy duty rear axle from a
common-but-not-popular large car to restore a popular-but-rare muscle
car (for example, using an 8-3/4 rear axle from a Plymouth Fury for a
Barracuda instead of finding the much rarer narrow 8-3/4). 2) narrowing
the rear axle to accomodate enormously wide slicks.

It has to be done carefully, and re-splining the axles may be the most
critical part. But yeah, its done all the time.

Most folks I know use a rim with a different offset or backspace to
adjust where the tires sit.

That said, it isn't uncommon to see shortened axles.  It's a pretty big
job though to get the alignment correct.  The person doing it needs to
know what they are doing.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...