I know they stopped making the Zaon MRX but I think it is a great little device. I'm sure there are lots of us out there that use one. However it eats up a pair of AA batteries fairly quickly. I didn't want to connect it to my 12 V battery as that is just one more load on the system. Because the Zaon is on the glare shield and always in the sun I got the idea of using a mini solar panel attatched to it. I made an Instructable on how I did this:
http://www.instructables.com/id/Sola...ilar-small-el/
It works! Total cost is about $10.