Professional Docbook indexing

Has anyone here hired a professional indexer to work on Docbook sources? 
If so, how did that go? Do you have any recommendations?

-- 
Elliotte Rusty Harold  
XML in a Nutshell 3rd Edition Just Published!
http://www.cafeconleche.org/books/xian3/
http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim