DES cycle lengths

Ned, back in the early days of DES I presented a paper to the IACR
concerning the expected cycle length of DES in Output Feedback Mode.
Donald Davies did a rather similar analysis, beginning with a different
set of assumptions. Although the conclusions differed slightly, the
average length of a DES cycle was absolutely huge.

If ANYONE has succeeded in finding a cycle in DES OFB (other than 
that resulting from a weak or semiweak key), I would like to know
the reference.