Special Cobras were of course part of the Ford Custom Car Caravan.
One is known as CSX 2048, factory paint red with black interior. It is still around.

Another one is mentioned in George Barris Kustomrama book. "We received a new 427 Cobra...."
We'd like to trigger all your knowledge to piece together a clearer picture. I recently found a never published shot on a norwegian website called digitalmuseum.no showing the early Ford Custom Car Caravan Cobra.
A Dearborn Steel Tubing brochure shows a Cobra that carries the same characteristics (wheels, emblems etc.) and has a special Hardtop installed that resembles the Le Mans Cobra hardtops.

Here is what he really thinks. 

The Custom Cobras built by Dearborn Steel Tubing and Barris Kustoms.

This picture by Ola Borge, shown on the digitalmuseum.no website may show the red Cobra CSX2048. Any information or other pics you may have, please share with us.

The below yellow paint Cobra was shown during a certain period of the Ford Custom Caravan. Is this the same CSX2048 or is it CSX 2046 or the third Shelby demonstrator Cobra?

The DST Cobra pictured in a Dearborn Steel Tubing brochure.

The later Cobra with a pearlescent organic blue and silver paint scheme.
Is this the same as above? I don't think so. Caption of this picture in the Barris books says, that they made a 427 Cobra, the hood scoop and the blueish side pipe are indicators. Barris says, everbody wanted to thear the big engine and that's the reason for the blueish shade on the pipes.