necessity of a roof

[foxxinabox at wideopenwest.com (Foxx (in a box))]

   i know that there are convertible sciroccos and cabriolets with extra 
body support rolling around out there with for the lack of a steel roof. 
but, what i'm wondering, would extra support be necessary if the frame 
of the roof is there and not the middle section? in essence, to convert 
the roof into one big sunroof? harebrained, i know. i just see these ads 
for new cars with a vertical sunroof rather than a horizontal one and 
wondering if the middle man couldn't just be skipped. now, on with 
normal life.

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