I live on the Western Slope of Colorado and my house is at 6600' elevation. We came here from San Diego in 2005. 20% horsepower loss is a pretty reasonable estimate. Your ECU should be capable of dialing back the fuel to match the available oxygen to run properly (13.8 to 1, or so). The atmosphere lost can be replicated by turbos, nitrous, etc., for short bursts, but hardly worth the trouble on a street bike, IMO. On my KTM 300 dirt bike I installed a high compression head to get back some punch. Problem there is, no riding at lower elevations without higher octane fuel. I didn't ride at lower elevations (below 5000') so I didn't care. I had a lower elevation jetting (5000-7500') and a high elevation jetting setup (7500'-12000'). This is probably impractical on a street bike that may be ridden at lower elevations at times. I would talk to Imperial Sportbikes in Denver. They should be able to tell you what's possible. That's my long answer, my short answer is "no".
