LDAP in php

As LDAP can have SQL back-end (I saw an example with PostgreSQL) - is it a very wild idea to implement (a simple) LDAP server in php? We have all the address data already in PostgreSQL and a php application managing all of it. I am thinking of simple uses, such as providing LDAP address books to Thunderbird/Squirrelmail users. For instance, is it too wild to think of Apache/php listening on the LDAP port (or so), get the request, parse it, get the data from PostgreSQL and send it back to the LDAP client? Iv