You can use DVD2AVI (http://arbor.ee.ntu.edu.tw/~jackei/dvd2avi/) to
indirectly edit dvd content without full conversion. It would produce a
psuedo avi file for movie maker to work on but essentially the frames would
be served from the dvd through the dvd2avi driver as required by mm. In
principle, one can also work directly on the (non-encrypted) dvd disk,
without even ripping, but that would be slow, i guess.