yup, those are the choices. none are especially awesome.
-used MJ shafts are getting hard to find and most every possible drivetrain has a different length.
-custom shafts from Dennys or Adams aren't especially cheap, but they are much stronger than factory. maybe you have a shop locally to you that can make one?
-2wd shafts are weird and have a rubber isolator on the axle end. it's possible to shorten them (I did), but you have to cut the t-case end and then hope the rubber is still good enough after 35 years.
the link in my signature has a thread with all the various MJ driveshaft lengths.