How about LEDs? Ok, here's how it could work, you have a thin circular light case (could be like 1/4-1/2 tall because LEDs are little!) there are LEDs arranged around it in a circular pattern, with, and here's the key! BOTH (or all, if we end up with more than two colors next year) colors of LEDs are in the case, and using the IFI software, the colors are controlled by the field equipment (or a switch on the robot/in the program). This means you would never have to worry about switching light lenses, and it would most likely be much less prone to breaking, as it is smaller. This could then be mounted on top of the robot, meaning you can see everyones, and it's not blocked!
LEDs can also be WAY brighter than normal lights like we have now, I know my team had some of those wheel lights, and they were much brighter than the competition light.
Also, you could do really cool strobing patterns if there were lots of LEDs.
The link is to a really poorly made picture, I hope it gets the idea across.
http://members.cox.net/johcagaorl/LEDlight.bmp