I too have been looking for a book on shrimps but not found anything other than foreign language versions.
There are several in German but this is not suprising as there has been much more interest in freshwater shrimp keeping in continental Europe than in the UK. Hopefully, as the hobby grows here, translations will start to appear?
The only one I could find via an Amazon search was: Aqualog Special - Shrimps,Crayfishes and Crabs in the Freshwater Aquarium by Uli Werner (Hardcover - 1 Jun 2003)
however, at over Â£30 it is a lot to fork out for a book I know nothing about.
Good luck with your search - let me know if you find anything!