At work, I have had my programmers code their work into the following naming conventions which basically read:

	class.{classname}.phps
	function.{functionname}.phps

Each file contains the code solely for that particular function or class, and then we have a system which autoloads all of these files at startup as if they were a framework.

However, as I look at our performance, which is not optimal considering the number of files we are loading per request when we only need a fraction of the code loaded, it seems like it would be a huge boon to have two new callbacks added to PHP:

	class_callback_func()
	function_callback_func()

Granted, each of these callbacks would have a price attached to them, but it would allow programmers to, and possibly positively influence them to, develop a 30 MB codebase, and then go wild worrying about your core logic instead of include()s/require()s/auto_prepends, while PHP automagically loads the proper support files to facilitate their programming.