Hi Matt,
Thanks for the post!
Adding a user is done in perl in the e-smith manager.  If you elect to do this yourself, you should review:
/home/e-smith/web-functions/users
and in particular study the function:
"performCreateUser" 
Ultimately, the idea is to add users to the file:
/home/e-smith/accounts
and then run:
/sbin/e-smith/signal-event user-create "user-account"
once for every new user you add, where "user-account" is the new user's account name.  
This can be automated in a fairly straightforward way.  The LDAP information is automatically updated as part of this process;  you might add a few users manually and then look at their data in the /home/e-smith/accounts file to see where the user and LDAP information goes. 
If you don't know Perl and/or if you are also planning on not using the e-smith software completely as intended out of the box, I do recommend working with us under our e-smith Developer Partnership, which costs $1,500.   
Thanks again for the post!  Good luck in however you decide to approach it. Let us know how it comes out!
Kim