running LDAP in user space with xinetd

[<amit@ls.net>]

We'd like to enable our customers to keep their address books available
online in the form of ldap directories. Is it possible to launch slapd from
inetd or xinetd in user space with the configuration files in userspace as
well? is there any way to give each user their own configuration file
instead of a few lines in the central conf file. As far as I can see now,
I'd have to give each customer their own branch of the directory and
restrict write access to that branch by username. Is this the only way to go
or is there any possibility of running slapd off xinetd in userspace with
userspace conf files?

I would like to use ldap for this so users can access their "online address
books" from anywhere with any email client with LDAP access support, but if
there is a better product out there for this task, could anyone provide me
with some leads?

Lastly, where can I find information on using LDAP with different database
backend types. Would it be possible to use LDAP with MySQL or PostgreSQL
database backend?

Amit