The coolest Tron keychains I've seen by far are the fluorescent acrylic ones they sell at gamestencils.com. Unfortunately, they've been out of stock for a long time.
http://www.gamestencils.com/index.php?crn=226&rn=469&action=show_detail
I sent them an email asking if/when they will be available again, but I never heard back from them. Maybe if enough people bug them, they will do another run.