My current sys.import_hooks patch implements #3 and I think that's the most logical thing to do; after all sys.path may not be meaningful for a hook. #2 makes little sense I guess. #1 could be an option, but, given the current state of import.c, would be a lot harder to implement. I also think that #3 is the most efficient scheme, as the hook can save some local state while traversing sys.path.

Have you looked at Gordon McMillan's import utilities? He handles this by having a "shadowpath" in the manager which maps sys.path entries to "Owners", where each Owner is responsible for loading from one location (directory, zipfile, whatever). I'm convinced you're reinventing the wheel here, at least in part. (But reinventing it in C, rather than Python, so it's not a completely bad thing :-)) Paul.