UPDATE:
I've written the PHP extension to allow for opening resources as files in PHP (called resopen, resread, etc. For not-yourself files, you can even write resources via a simulated stream interface, but that's a memory hog for large files. I may work on self-rewriteing, but I wouldn't count on it.)
Additionally, using a bit of code from Back Oriface 2000, I've managed to get PHP to load its DLLs from it's own resources (Resource type: DLLDATA).
The next step is to have php bootstrap from win32.res://self/phpscript/1/1033, and to write an fopen wrapper (into php_peres.dll) so that resource files can be accessed with the existing file-handling functions.