When I had my truck first painted sometime in the mid-80's, I wasn't sure what I was going to do with my dash pad. The colors were going to be blue and silver, and the dashboard and other interior pieces were red, plus the dash had some large cracks on it's top. The guy that painted my truck said he wanted to try something that he'd never done before, and if he could use my dash for his test, he wouldn't charge me anything for the labor or materials. He also wouldn't tell me what it was that he wanted to do. (He was an awesome guy, and really enjoyed messing with my innocent, naive 17 year old self.)
A week or two went by, and he finally let me see the finished product. He epoxied over all of the cracks, and laid down multiple tones of tan and brown in a way that looks like some sort of wood grain that you probably couldn't find in nature. Then he topped it off with a shiny clear coat that gives it some great depth. Eventually, the cracks came back through the paint. But the paint has held up phenomenally well! Since it's all automotive paint now, instead of using Armor All on it, I clean it with a mild car wash soap solution, rub it with a clay bar as needed, and keep it waxed the same as any painted body panel.
I don't know exactly what he used to patch the cracks, he just said it was 'epoxy.' It could be anything...J.B.Weld, fiberglass, Bondo, some of that vinyl repair putty. I saw some plastic welding rigs at Harbor Freight within the last few years, and thought something like that might have lasted longer. Although, it's not too bad for something that was done over 25 years ago.
If you wanted to know more about what or how it did that, I could find out if he's still alive and get you his contact info. (I hope he's still alive...he was definitely a character!)