As it has been discussed in the @dev mailing list, CouchDB should be configurable to use customizable password storage/hashing schemes.
Brian Candler suggested the support for the OpenLDAP schemes for example.
From the Auth roadmap mail chain:
"1) Extensible password storage.
Thanks Brian Candler for the links to the OpenLDAP style of storage. I
think we should do this asap so we don't have to worry about backwards
compatibility with the current storage mechanism until the end of
time. The relevant message: