I think Dino hit the nail on the head. The heat shield does not affect performance and is there mostly for safety. I haven't had any problem with it on my VX yet (but then I've only been a member for a short while and preferred to concentrate on the other VX SNAFUs first - windows, CVs). I've removed most of the heat shields from my TLC over the years (as each succombed to cancer - believe it or not there were six). No problems since. Now for the horror story though - I have heard of carpet melting because the exhaust system got too hot close to the underbelly.

I would not try for a factory replacement. You should be able to find a shop that could fab something up for you @ less $$$ and would actually last longer. Metal tape will work but my experience on an old Dodge P'up was that it is very temporary.

I've seen some ceramic coatings in the past but that was very long ago and probably are very $$$. I've also seen some fiber wrap for exhaust but again long ago and very $$$ - it also wasn't recommended as it would PROMOTE rust.

I'd recommend some leg work to find a small shop with a good welder that could fab something up for you (I'm lucky - I found such a place). Don't bother with the big chain shops. Find JoeBillyJimBob who operates out of uncle Mikey's garage. The big shops probably won't touch a job like that for liability reasons.