OK ... I mainly introduced two new constants DOKU_TPLBASEDIR DOKU_TPLSEARCHDIR I modified the files mentioned in the Bugreport to make proper use of them.Additionally I modified the "setting_dirchoice" class in config.class.php, so that it accepts a String with multiple dirs separated by an colon. So it is possible to use templates from the default and from the individual path.
I decided to not modify the css.php but rather omit the parameter "t" in the template.php.
It works for me but I just a quick "see if it's running" test.OK I need to leave now. Hope its not to weird and enough to discuss on this weekend.
Roland