Does anyone offer a NEW cab?

[TP from Cntl PA]

Me and my brother talk about this quite often and I keep forgetting to ask about it on here, but the thread about why these trucks are so popular jogged my memory.

You can buy just about every part new for these trucks other than a frame and Cab. Of-course, frames seem to have survived the years quite well and even in the rust belt they still are in decent shape. But the cabs on the other hand seem to be all patched and repatched. I am curious, why doesn't anyone offer a reproduction? It seems to me that the demand is there, I know I wouldn't fart around with putting in rockers, cab corners, cab supports and who knows what other junk when you could buy a new one even if it wasn't cheap, but it would be right and not all hacked/patched up. I know I'd rather have the advancement in metalurgy and rust prevention over the OE. Someone mentioned Fiberglass..........I haven't heard of such a thing, could you fill me in? Is the DOT the main reason they are repro'ing the cabs?

The K-20 I just bought needs some attention to the cab, but the rest of it(Western truck) has very little rust on it and it drives like a new one. If I could have a new cab to pop on that beast I'd practically have a new truck that would last me a long time.

Could someone enlighten me about this subject.