Couchette is an experimental implementation of CouchDB in C, funded by Codethink. It's using GLib and in particular GVariant for the on-disk storage, combined with a write-append btree implementation from BZero's LDAPd implementation for BSD (http://www.bzero.se/ldapd/).
Currently get crashes appearring from unaligned gvalues. Multiple aspects to this, currenlt working on adding more debugging to gvariant to help figure the issues.