We could do the same for cascading style sheets. Place those in /www/resources (either package specific or global).
I think this is the first half of what needs to be done for really useful CSS on a package by package basis -- which is the essence of "cascading". The second half (since the <link> elements have to go in the <head>, which is probably handled by a global template) is providing a mechanism to pass stylesheet references as properties up to more general templates or have global templates look up package stylesheets (by package id?). The former is probably be more useful since it would allow more freedom to specify particular stylesheets when necessary.