I've been looking at setting up Redmine, Trac, or JIRA to track issues. I want to be able to have my development team create internal tickets that are never seen by clients, while clients can create/edit tickets that are seen by the internal team.

From the Trac documentation, you can set permissions to create or view tickets, but it doesn't seem to allow for viewing only certain tickets. It may be possible with Trac Fine Grained Permissions, but doesn't appear so.

The Redmine documentation mentions:

Define your own roles and set their permissions in a click

but doesn't appear to have the level of granularity.

From the JIRA documentation:

At the moment JIRA is only able to support security at a project level or issue level. Currently there is no field level security available.

According to this question, Redmine doesn't support internal tickets, so you would have to use multiple projects. I don't want a situation where I would have to create multiple projects - one internal, one external and have the external tickets brought into the internal repository. It seems as this would lead to unnecessary overhead and inevitably, the projects wouldn't be in sync. Is there any way with any of these products (possibly through a plug-in if not in the core product itself) to specify these permissions, or simplify having two projects with different users and permissions that must still share information?