I have Trac setup on a separate server than my eBox server but it does authenticate against my eBox's LDAP. Trac was easy to setup, I basically just followed these instructions
https://help.ubuntu.com/community/UbuntuTracHowto (after looking at it though it looks a little more confusing and messier than I remember it, might write up a full how-to later.)
After you have trac setup though here is your apache configuration for authenticating against your LDAP.
<Location /trac/>
SetHandler mod_python
PythonInterpreter main_interpreter
PythonHandler trac.web.modpython_frontend
PythonOption TracEnv /home/trac/project/
PythonOption TracUriRoot /trac/
AuthType Basic
AuthBasicProvider ldap
AuthName "Ebox Login"
AuthLDAPUrl "ldap://YOUREBOXSERVER:389/ou=Users,dc=ebox?uid?sub?(objectClass=*)"
Require valid-user
</Location>
All permissions, etc will still need to be handled through trac which should be easy through tracs admin interface.