As the others have stated, there aren't any (that I'm aware of anyway) that will import directly to iMovie. You first have to transfer the files from the HDD camcorder to the Mac HDD, then convert them from their camcorder format (usually .mod, or some other odd .mpg type format), then import them into iMovie.
From my experience, The conversion of the files is only slightly faster than capturing from miniDV. I like the HDD only because I can go in and delete a clip directly from the camera if I don't like it without having to rewind and being worried about over wrting some other part that I want to keep.
Best,
Brian