I've been wondering whether anyone has tried using original equipment shifters from other BMW models on their X5s; I know that for the e28, e32 & e34, the shifter from the Z3 is a popular alternative to aftermarket short-shifters. Provided the pivot ball and bushing where the shift rod connects to the selector rod is the same, I don't see why it shouldn't work.
E28 Shifter FAQ - MyE28.com