You are making the solution a little complicated. Just make a new user interface package that can aggregate the content, and set the permissions accordingly. Make use of includes if the original package has similar pages that you can use.
In general I think making alternative UI packages that reuse a data model is a very good way to develop new applications. I recently build a new user interface on top of the survey package.
One interesting idea is to just restrict the display in such a package based on read or other permissions on the objects instead of the package_id.
You can do this without making any changes to existing applications.
To address the management issue I developed a couple of options. If the aggregator package was visited from a single instance, the links to the aggregator passed in a package_id which was stored in a cookie. Any actions that required a package instance would be done on the one stored in the cookie. If the cookie doesn't exist a list of packages the user has admin over is given.
