In my firm, we need authentication and authorization on hudson.
For authorization, LDAP (or Active Directory) is perfect.
But for authorization, the matrix-based security is very too limited.
We need a matrix-based but on a part of jobs or views or a regex, not for all projects.
For instance, if you have 2 applications (APP1 et APP2), (a view for each like APP1VIEW and APP2VIEW) with 2 jobs, we need to have the possiblity to set that the developpers of APP1 can launch and read jobs from APP1 or APP1VIEW but not for APP2VIEW what it is not possible to do today.

It is very important for large firm where some source code is sensible for security reasons.