[mod_python] Which handler? (WebDav AA system)

I'm trying to build a simple handler that will multi-user WebDav
storage. Of course I intend to use the DAV support in Apache, and just
want to write a simple wrapper that will allow or deny access acording
to some criteria. It seemed to me that I'd that easyest with python
and mod_python.

A bit of context.
WebDav uses several HTTP methods, but we can generally separate them
in two classes: GET&HEAD are public, every other can be considered
restricted. My idea is that a user has full rw access to his own part
of DAV storage (for ex. '$DAVROOT/username'), everything stored there
is publically readable unless stored in the special folder
'$DAVROOT/username/private'.

Now, the question is what handler to use.

I tried the accesshandler, but it seems I can't return
HTTP_UNAUTHORIZED from it (it gets converted to FOBIDDEN somewhere).

I tried authenhandler, but it needs peculiar setup in apache's
configuration, and it requires authorization no matter what.

I also tried PythonHandler (and SetHandler mod_pytohn) but the problem
is that it doesn't handle requests for methods other than the standard
GET, POST, etc. (it misses PROPFIND for ex.).

I tried inithandler too, it seemed like it doesn't execute.

So the question is, which handler I can use so that I can allow public
access in some cases, FORBID access in other casses, and ask for
authorization in third cases?