I've mounted this handy little accessory on both my Tourer and Interstate:
http://www.bikebandit.com/emgo-handlebar-mount-cigarette-lighterIt mounts horizontally right beneath the fuel switch and is held firmly in place using one of the existing bolts joining the coil support bracket with the engine hanger.
I use it to light up my favorite cigar or, with the proper USB converter, charge my iPod or iPhone. Waterproof too!
Steve