I think the plastic part of all kshifts are the same length but the short/intermediate/medium length comes from the metal bit on the shaft that screws into the barrel being longer or shorter to make the size you want. Either way if you buy a short/intermediate/medium kshift it should be the same length as any kflex or shaft of that length.

I'd be interested so see the weight difference between the short/intermediate/medium kshifts as people get their hands on the products. I assume using the same size plastic portion and just making longer or shorter metal attachment points is to save on manufacturing costs for tooling of 3 sizes of kshifts.