Fully integration Redmine-SVN (as Gforge-CVS)
In my company we implemented the integreation Redmine-SVN this way:
Redmine can read SVN (default);
User accesses Redmine via LDAP;
Users added to projects via Redmine (default);
Permissions of checkout/commit in SVN varying accordinly to if the project in Redmine is public/private (default);
Access to SVN verified via Apache - it looks for the entries in Redmine DB if the user is a member of the project, then can checkout/commit, using login/password from LDAP.
But this integration is very simple: if the project is public, anyone can make checkout but only users added to the project can commit. If the project is private, only members of the project can checkout/commit.
It would help if the access to the DB was totally controled by Redmine: using roles, we could define which type of access each member has in the repository (viwer, only checkout, only commit, free access, etc).
As comparison, Gforge does this integration with CVS.