I've been pondering this very thing for a while now but for a 250cc cruiser with an ultra low seat height, kind of like an Alligator. So far I've found only two fairings available but both would need significant enough modification it would be just as easy to start from scratch anyway.
One is a classic "dustbin" reproduction like your sidecar pictures.
http://www.airtech-streamlining.com/.../MV1751965.htm . The same company has gobs of race and reproduction fairings
The other is Craig Vetters reproduction Rifle body.
http://www.craigvetter.com/pages/470...20fairing.html