http://www.ebay.com.au/itm/STEALTH-MOTORCYCLE-FLIP-NUMBER-PLATE-SYSTEM-HONDA-KAWASAKI-SUZUKI-HARLEY-/261178776739?pt=AU_Motorcycle_Parts_Accessories&hash=item3ccf77dca3

 

Since they already have these things for cars it would already be illegal.

 My HD side mount plate does the job just fine, don't need any switch, I just simply lean and reach back