If there is, I haven't heard of it. On a semi-related note, over on the COG List, one of the guys who has done a lot of work to get more oommph out his old engine was surprised to learn that blocking half the intake area into the airbox gave him more hp and more torque -- verified by dyno results. I think he gained nearly 15 hp, and several lbs/ft of torque.
There is another guy, a Presbyterian minister who was no doubt predestined to do stuff like this, who has turbocharged and fuel-injected his Concours. He says he can pull 150hp out of an engine that most of the time was credited with about 90 rear-wheel hp.
So, there you go, Igo, you can accept the challenge and be the first to have a blown NT.