I have two versions of Radio Shack's tape loop box. No, not THAT kind of
you sillies! It is designed to connect to your receiver's tape loop (tape
and outs) and allows you to have three instead of one tape deck connected to
your stereo. It allows dubbing between any of the three decks, too. This
be ideal for your purpose. Unfortunately, the shits at Radio Shack have
since discontinued this handy little device. I guess not enough people are
me and want to connect a DAT, a Cassette, a minidisc, and two VCRs to their
stereo tape loop. Go figure!