Shimano Ultegra

Shimano Ultegra
Shimano Ultegra 6500 Jockey wheels?

Does anyone know where I can buy new jockey wheels for my Shimano Ultegra rear derailleur?

from here
http://www.chainreactioncycles.com/Models.aspx?ModelID=28108
But often I have found it is almost as cheap to buy an new derailleur than the 2 jockey wheels.

Shimano Ultegra 6700 – first ride