One idea for this would be to buy a sheet of Kydex or ABS and thermoform it into the desired shape. Kydex in particular is pretty easy to work with once you've got the knack with the thickness you're using. For this application, I would think .060" or .080" would work strength-wise, while being easily molded. You would have to make a mold since I doubt it would be possible to form it by hand, but it might be worth a shot if someone wants one badly enough. At that point, you could get creative, even flanging it so that an original A-pillar could be cut and bonded with the gauge section as a level, smooth transition. Though I have no real interest in a pillar pod, I do plan to do some experimentation with Kydex in other areas of the interior of my car.
The trick with Kydex is it's not as easily bonded to itself or other materials as ABS, but it's still not terrible. There are adhesives available that will hold the stuff, but some of them are pricey. Devcon Plastic Weld is supposedly one of them, though, and that's not terribly costly.
Ten million thoughts and ideas running through my head this winter, and it's too bloody cold to do anything about most of them. Grrrr...