Hi Peter, I'be followed your previous postings about motorcycle body designs and I get where you are coming from
Unfortunately there is no easy answer to your quest (I've been looking for it myself) because of the complex nature of "side lift".
Lift has two components, Newtonian and Bernoullian, and you are searching for a means of eliminating the side force ONLY using Bernoulli's principle. Even if you were able to do this ( as your question implies) it would still leave the Newtonian component, which as it applies to motorcycles is the greater of the two forces.
A useful explanation can be found here
http://youtu.be/zUehWUoiPHQ
Your efforts to reduce sidewind sensitivity should be aimed at reducing the "sail area",and lowering the Centre of Pressure (ie height above ground). This will reduce the turning moment around the tyre contact patches and reduce the lean angle, thus aiding stability.
One of the central problems with traditional motorcycle design (ie those that keep the normal hands first riding position) is that a high centre of gravity also implies a high centre of pressure
Attempts to enclose the upper body area of a motorcyclist will inevitably result in a large "sail area", high above the contact patches, and therefore a large overturning moment.
To make any real progress in this area you will need to consider recumbent riding positions or active aerodynamics.