High intensity 1156 bulbs have been available for a long time- I've used them in my CRX's for over ten years (same # bulb). Just added a pair to the DSM. If you can't find 'em anywhere else, try JC Whitney- they have 50watt bulbs available.
http://www.jcwhitney.com/DESIGN-TEC...GN-TECH-50-WATT-HALOGEN-BACK-UP-BULB/GP_2003659_N_111+10201+600002844_10101.jcw
BTW, I recently installed a wired backup camera onto the license plate of my Spyder- visibility out the tiny rear window was a problem for my wife (5' 4"). For the display, I added a motorized single-DIN 7" video unit in the top slot of the double-DIN dash opening, moving my Pioneer head unit to the bottom. In that position, it easily clears the shifter knob as it slides out, then flips-up in front of the HVAC controls. Pretty neat- the camera outputs a 0-4 ft grid pattern on the screen display that gives a reference for what distance objects are behind the car. And when it isn't being used, there's no big, obvious screen to attract thieves. One thing I wish the backup camera had is an auto-iris. If you adjust the screen brightness down enough that the field of view doesn't wash-out during the day, the image is rather dark for at night. Which is why I just added the HE bulbs.
