More aerodynamic class C sleeper? Angled roof?

[aerohead]

I went back through Hucho's text in the section for roof camber:
*Only a notchback car is analyzed
*Roof convexity drag reduction peaks when the height of the 'bump' is 17.5% of total vehicle height.
*If the convexity is designed such that frontal area increases,overall drag increases.
*The convexity lowers the Cd by 5%.
*The added frontal area caused by the convexity raises the drag factor (CdA) by 4%.
*Net overall drag increase is 3.6%.
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*In 1992,box trucks has Cds ranging from Hino Diesel Trucks (USA) Inc.'s industry low of 0.52,to up to as high as 0.82 for the competition.
*In 1988,Leyland DAF's,Besco Bodies of Northampton,England's aero-modded box truck demonstrated Cd 0.325.
*Besco used a radiused roof (like your BUDGET Rental truck),cab air dams,and a DOWNWARD SLOPING ROOF.
*Besco claimed a 40% mpg improvement at 60 mph.
*Cost of the modifications were $2,000 in 1988 dollars.
*No photograph was provided in the Pop. Sci. article.
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I've brought some additional boat tail images.Perhaps we can get those scanned and uploaded to PHOTOBUCKET so I can post them.We'll see.
Here's a link to a 1978 NoseCone add.
http://www.nosecone.com/images/aboutpic1.jpg
http://www.sae.org/dlymagazineimages...2815_18313.jpg
http://www.sae.org/dlymagazineimages...2815_18311.jpg
http://www.tc.gc.ca/media/images/pro..._eng_fig23.jpg
Here are some designs dating to Calthrop's wind-resisting train of 1865