I've been talking to Getor via PM about the size of number plates and thought...why don't we replace the metal license plate with an LCD display of the same size? A small tablet would be perfect.
Now, think of it programmed to display your license plate in all its glory, same font, color scheme etc. But it also has a GPS, so it knows what speed you're going and your location, so it knows the speed limit...you know where I'm going with this, don't you?
10 mph over the speed limit and the license plate starts to lose resolution, go all fuzzy and hard to read. 20 mph over and it blanks out. 30 mph over and it shows your ex's new partner's number. 40 mph over and it shows a picture of your arse, with you bent over to give a perfect full-moon. 50 mph over and it shows your speed!
You could also connect it to your GoPro at the front of the bike to make it look like a hole cut all the way though the bike.
I think I need to lie down now...or get on kickstarter...