Here's one of my attempts at using an F and C to make a "hat" http://jef.is-a-geek.com/F-C-hat.png the F and C are standing upright http://jef.is-a-geek.com/F-C-hat2.png rotated 90 degrees into a "hat"
again.. its rough.. but I think i can get an equally rough "hat" using an L for legacy or an E for extras instead of the C.
Something like this gives us the abstract hat without it meaning to be a hat at first glance and might be able to pass the "no hat" criteria.
-- nicu Open Clip Art Library: http://www.openclipart.org