The right hand front 2 piece axle has a center carrier sealed ball bearing enclosed in a casting. BMW does not list the bearing separately. The entire rebuilt axle is over $500 USD retail.
I have found a source for the bearing that works.
You will have to separate the two sections and then tap off the bearing housing after removing a large snap ring. The bearing will then have to be pressed off the shaft at a machine shop. Also the race for the seal at the transmission end will also have to be pressed off. The new bearing is 2mm thinner than original, but is so close as to not make any noticable difference. The cost is $52 USD for the part.
Manufacturer: SKF
Bearing Number 62207-2RS1
Kaman Industrial Technologies
(315)-797-1590
http://www.kamandirect.com
Specs:
https://ec.kamandirect.com/kamandire...equestid=20440

 

Reviving an ancient thread here. This bearing is now $130 at that source for some reason. Searching the part number I found it on ebay for $38.