Hi, my company daftdata ltd over the pond manufactures a range of wireless dmx products, we have a beltpack reciever which works using standard 802.11 wireless ethernet to send the data.
If you are after something that could remotely dim a 12v 50w (LV) lamp then i think that a US company citytheatrical might have what you are looking for. If you need any more info please feel free to drop me a line at chris@daftdata.com
Regards
C