Originally, Tuxbrain sold the Ben NanoNote as the initial, official EU reseller. However, they appear to have stopped selling hardware. Fortunately, some other EU resellers stock the Ben NanoNote and related products:
A continuing effort to list open hardware vendors is being made on a number of sites including this page on the FSFE Fellowship Wiki. Information on new vendors should probably be sent to the maintainers of such resources as well as being added here.
See also the Shipping Notes page for details of other resellers.