You can definitely get new windshields for your '67. I got mine about two years ago. It's not Carlite but PPG. My recommendation is if you have someone put it in for you, get a good shop that gives a guarantee on their work. I went to one that didn't (DOH!) and after two times going back to them for leaks, it still leaks, so I need to find a better place to do it again.
If your looking for NOS....good luck. I think there aren't many out there.
You can find off-brand replacements starting at $150 on up to whatever god-awful price they are getting for NOS. I have no problem with aftermarket glass, but be aware that quality can vary a bit. Almost all replacement glass is thinner than the original by quite a bit. This causes trouble because the new gaskets are made to fit the original thicker glass. It can be sealed with some care though.
BTW, the thinner glass is not just because they just make everything cheaper nowadays. There are some excellent safety reasons involved. I have "face-tested" a windshield and have the scars to prove it. Believe me, the thinner windshields are a GOOD thing.