The next thing that bugs me most about the current PHP code is the stylesheet/skin handling, so I'm thinking about tackling that. But I'd like to get some feedback on some potential changes:

First off, we're currently using inline stylesheets instead of linked stylesheets. The latter would reduce bandwidth while allowing more customization, and clean up the code considerably. Is there any popular browser that chokes on linked stylesheets and might therefore be a reason to retain them?

I want to make each skin a PHP object type, each of which inherits from a common base type (and possibly one of its subtypes). Is there a way in PHP to only interpret the class definition code on-the-fly for the needed type? For example, if our user has chosen the Startrek skin, can we avoid loading the file that defines the Cologne skin object? This might require getting tricky with include() and defining classes within a outer class def, and I just don't know PHP that well.

Any other gotchas I should know about?