Over the past few days I've realized that what would really make sense was to be able to put up pages anywhere, in any package.
For example, at http://www.collaboraid.biz/events/, we've put up a page about accomodations, which obviously isn't part of the events package, but logically, the page belongs under /events. Another example would be a posting policy for forums. Or the forums index page, which lists the available forums, which I could very well see you wanting to customize so some forums are displayed in a larger font than others, or some other graphical means of emphasis.
The point is that if you're stuck with only what the application provides, you're limited in how effectively you can communicate, when it comes to applications that are both functional and informational.
The next step would be to be able to use ETP to customize the package-provided index.adp, event-info.adp, and similar pages, which are part of the application logic and live in the file system. But really, being able to mock with them on a per-package instance level would be really useful. Think also a blogger.com style site, where each individual blogger can change his templates through ETP.
The next step again would be to allow you to change the event-info.adp page, not on a per-package-instance basis, but on a per-event basis. I think something like that is really required for something like an events package, where the way you do it, and what's important, can differ in so many ways, as events really aren't just, and never will be, events.
Do you follow me?
The next question to ask, of course, is about implementation. What's ETP's relationship to the packages for which it defines pages? Another applications which I could see provide functionality like this would be and Portals. In combination with ETP. And depending on what it turns out to be, ETP is just a special variant of a CMS application.