can/has it been done?? home made headliner...

Just quoting you guys making sure you're seeing this finished product..
It's a great big piece of special paper/cardboard/ etc. laminated or painted to give it a texture and then die cut on a really big clicker press. It's also got to bend and curve to fit the contour of the roof and to meet up with the creased edges. Unless you're seriously into origami and have pro upholstery skills I'd ask a local car upholstery shop what they'd charge, if for nothing else than to get an idea of the work involved. I'd wager they'd charge as much or more as just buying one. Short of that I'd try to find a used one and cover it will some new material. Or sell some stuff from your spare parts bin(?) to just buy a new one. Another alternative might be to put a cloth one back in it, if the sill area was made to accept the clips that held the bows in place. Not sure if once they went to cardboard liners if they stopped punching those holes for those bow fasteners.
Bed line the inside of the roof. Only your hair dresser knows for sure.

The compound curvature of the pressed paperboard composite headliner is a mo fo. It takes steam, precuts, and forms to get the shape right without wrinkles.
This is all good to know as I will leave mine the hell alone even if it is a bit scarfy
I took a very beat up factory hard board headliner and with Duct tape and other methods of red neckery I fixed it up to the point that once I covered it with cheap black upholstery vinyl, it looked really good. The only down side is that when I attempted to install it, I realized it was for a Dart (square roof) and I have a Duster. Didn't fit after all that. If you can find any type of an original headliner, in decent to poor condition, you can do the same. The vinyl was about 30 bucks and a can of spray adhesive was about 15. That's all I had invested so I don't feel bad that it still hangs on my garage wall!

Cley
I put a fair amount of thought into that subject before I painted the heck out of my cardboard liner with flat black using a roller.
I was thinking that house siding insulation foam boards, contact cement and my heat gun.
Then cover the foam with that thin netting backed foam rubber material they use for upholstery once the foam was up, and material over that.
The foam rubber reinforced with netting should hide the seams in the foam.

A good insulation between me and the metal was also a priority living in AZ.

View attachment 1715108180
I bought the plastic headliner as I didn't have the time to much around with trying to make a cardboard one. It can be done.. Look online as the plastic ones and it'll help you with where to place relief cuts.

I'm planning to cover mine with thin insulation foam (1/8 or 3/16") and then black vinyl or suede.

Riddler
Like the other guy said, "bedliner"!!!!!!!
I had my old one recovered by a friend that does interiors for $0. He used a modern foam backed black cloth that has tiny lines in it. I think it came out great as is a better insulator. I also insulated the roof with reflective foil sound deadener.

The second one I did myself (different car) using 3M headliner spray glue, and foam backed material off of EBAY. The only hard part was removing all the loose foam from the old cardboard and fixing the corners which had water damage. 6 years later it still looks fantastic. So don't be afraid to tackle this job. You can do it!