Randall Washington of Randakk's Cycle Shakk has been working on a supercharger kit for the Honda GL1000 and GL1100. He has it on the road now so it should be available before long. The kits will all be custom fabricated when you order. The blower is a positive displacement, twin rotor "Roots type" supercharger that will output 6.0 psi max at redline. The target is a 25% increase in horsepower at the rear wheel.
It looks like the kit will be fairly comprehensive and he estimates about 30 hours of installation time which means you're looking at some serious work but these early Wings are still very popular and the payoff in performance for the big Honda may be substantial.
We covered Randakk's GL1000 Endurance Special earlier which looks really sweet. Just imagine that puppy with a blower. I like it!
Link: Randakk's Cycle Shakk