Timo - I agree about putting the default template in acs-subsite.
Lars - after looking into things after our discussion earlier today why can't you just use "resources/foo.gif" and ignore the url to the mounted package? If for some reason you *really* need a URL to the package that is guaranteed to work, why not use [ad_conn package_url]? I don't know why the dotlrn package was written to reference /dotlrn in hardwired fashion, but changing to "resources/foo.gif" works just fine...and packages shouldn't be cross-referencing small graphics buried in other packages (other than our current kludge of using acs-subsite/www/shared, something we can fix as we get time)
I'm also adding a suggestion made by Jeff Davis: disallow execution of scripts in the unchecked resources directory. Actually I'm only allowing one to reference .png, .gif, .jpg and .css files - I suppose we could parameterize this but is it necessary? Packages need to be able to depend on a set of extensions being guaranteed to work and parameterizing the list would allow the site admin to break everything.
We also discussed using ns_returnfile to quickly return such content without going through a bunch of request processor codef. I've reviewed the code that's executed when the request processor is in performance mode, and the path through the code to the ns_returnfile used to return non-script files is quite efficient and I don't think any special treatment is necessary.