I've done this with the kenwood dnx520vbt. Bought a number plate light of eBay for £25, the kenwood has the Rcam input so as soon as u activate reverse the canbus recognises it and flicks it on. Got no error from the new number plate light so it would seem that the number plate lights don't give off a bulb error! Was a nightmare feeding the cables and we took a power feed from the 12v socket. Great picture and well worth it!