Icon themes

In many places the use of icons makes for a nicer gui. In order to get a more unified look, it doesn't make sense if every module brings along it's own icons, but it should be able to ask the system for an icon by a functional name.
I think we need such an API in drupal core, but for prototyping and discussing a module in contrib should be fine.

In order to do that I have started a project: http://drupal.org/project/icontheme

There's no working code yet, but a rough conversion of the pseudocode from the icon theme specification, and some thoughts about how the api for other modules to get an icon should look like. I'm hoping for a lively discussion.