Have you actually gone to a store and looked up the mfg part nbr in the books they have on the aisle? After reading that BMW is putting the rubber refill blades on the NLA (no longer available) list...while walking around a local Walmart...I stopped in the wiper blade aisle to see what my future costs would look like.
I remember that the not all of the brands that were being sold offered a replacement blade for the rear. They all had front wiper blades...but some only offered rear.
Not sure where you've looked...but you may be successful physically checking out a "brick and mortar" store to see what brands they offer and what is actually in the catalogs they have on the wiper blade aisle.
EDIT: just did a quick online check using Autozone...and they only have front wiper blades listed for BOSCH refill blades...but they do offer other brands that have front & rear. Click the following link for a list of blade refills sold by Autozone for a 2000 X5 4.4i:
http://www.autozone.com/autozone/par...lade/_/N-8gcw1