I also liked ixion's "fifth" but my reasoning (after much debate with myself) was along the same lines as ab.
Among my "shorter" list were les40 @ 29 and peterm @ 32 with my vote going to ixion's other clue @ 13.
I was working on a Plan E idea before I found it had already been snaffled. I too liked ixion's fifth (should have been fourth) amendment but I'm going for jws's post 22.