No, there really isn't a PostgreSQL and/or an unsupported mechanism that will get you the exact behavior you're looking for.
The closest you're going to get is to use Trusted Tickets with an unrestricted ticket, and embed the portal's "worksheet" view as the default view in MOSS. By default, a Trusted Ticket will restrict/forward the user to a single view/dashboard. However, if you don't specify a view when using a trusted ticket, the user will be able to browse around in Tableau as they're used to. SO, but combining an unrestricted Trusted Ticket and making the default landing page of Tableau the "views" view, you'll land them on a list of reports that they have permissions to see.
Until we get an API that you can call directly, this is probably about as close to what you want as you can get.
It has been a while; I hope things are well with you.
I figured you would be the one to get back to me...thanks a bunch - I will kick your idea around and figure out what we will do.