I've always thought the R-Pentomino would be a good hacker emblem, as a shape that was once considered wildly unpredictable, but is now widely understood. The advantage over the glider is that all the cells are edge-connected, so you can make a solid object out of it. A necklace, for example. Try to make a glider necklace without that one corner-connected cell breaking off or whatnot.
One of the <a href="http://www.cafeshops.com/freedesktop">commercial sites</a> has a window sticker in the "Auto Goods" section, but I think this logo would be perfect for fuzzy dice.
Just what hackers need, an escoteric emblem that everyone will just mistake for connect four or tic-tac-toe. Considering that real hackers don't call themselves such, having an emblem seems even more of an anti-indicator.