Is it possible to change the URL inside feeds so they point directly to the articles instead of using DispForm? We don't want to open lists to anonymous users, so making the URL point directly is the best solution.
The RSS feed generator in SharePoint is basically a black box that doesn't give you the configuration options you are looking for. You could do some custom coding to accomplish this.
You could create a custom web service that runs in the SharePoint framework, see http://msdn.microsoft.com/en-us/library/ms464040.aspx for an example. Then make that web service return an RSS or ATOM feed.
In your service, you would just need to read from the list and format the data how you want it to be displayed in the feed.