M/C class ?

[tortoise]

Rulebook, Section 7.E.:

7.E.1   PRODUCTION
A production motorcycle . . . must appear identical in all respects to the production model it represents

How about replacing the seat structure and padding with low density foam, giving it a normal appearance but getting the rider's butt a bit more out of the wind?

[JackD]

If it looks like the picture in the book and the modification is out of sight, you may have arrived.

[sockjohn]

Right now there only 3 bikes in the World that take full advantage of the Class A rules.
One was run in 71, another is just finishing up, and the third is under construction.

Would you be willing to expand upon this? I'm picturing a rear-engine laydown layout like a streamliner, but open. A scary thought.

NOPE, you will see them soon enough and if they satisfy you they work, you can do it too.
Recumbent petal bikes have a very dedicated following don't they, the 3 that I am speaking of are better ?

"Timing is a real important part of rain dancing."

I should be at Bonneville this year - as a spectator    I look forward to seeing this!  I'll bring you a cold one 

I thought there was a seat height restriction in A?  recumbent "lowracers" have very good aerodynamics even without fairing due to low frontal area, how low can you make the seat?

John