I've posted high resolution pictures of the IR trackers that we built to test the IR receiver/tracking/navigation software. You can find 'em here:
http://kevin.org/frc/tracker. The trackers that we built for the kick-off demo consisted of two lego-based arrows that had a sensor hot glued to each of their sides. The lego arrow assembly was then secured to a servo.
I'll soon have software that will allow you guys to try out the tracking functionality without having to run the navigation software.
As this stuff is pretty easy to fabricate and has a high potential payoff (more game points, knowledge and fun), I'd encourage you to try this technology out.
-Kevin