my vote is with using a bmw shifter from a newer Z4 or Z3, like D. Clay said.
personally though, my opinion of getting a short shifter is for lack of shifting ability (on our cars at least), if your a decent shifter the stock unit is far superior to any other shifter because the engineers at BMW designed that lever for our transmision, and if it was better and more sportier to get a short shifter they would have put a shorter shifter in there at the factory. just my 2 cents.
save your money, just change all the bushings in the linkage.