My father is a watchmaker from way back. He still repairs watches and clocks for people - most often old cuckoos. It's not unusual for him to have 4 or 5 in the downstairs room running, so he can get the timing right. Kind of funny, as he likes 60's modern, and considers them hideously ugly.
Anyway, he is also a model builder (plastic kits), and recently aquired an old Lindberg kit of an old fashioned (13 century) clock. Molded to look like wood, it's all plastic except for the chains that hold the weights. Surprisingly, it keeps perfect time. Looks a lot like the paper one, but a bit more ornate.
Another story, this one involving *gasp!* wood. My dad has aquired a good reputation in his clock repair, and word has spread. Seems a friend of a friend of a friend had this really ancient cuckoo clock, made in Germany or Austria or somewhere like that. Made in the late 1400's to early 1500's, it had passed from generation to generation, and was considered the family treasure. Very ornate, to the point of being obnoxious. Worth a small fortune, except for one detail: it no longer ran. Still, being so old and nearly flawless in appearance, it was worth many thousands, and completely irreplaceable. So, with some trepidation, he approached my father to inquire about fixing it. Opening it up revealed one of the main gears had lost a tooth, sheared clean off.
Now, you have to realize that making a new gear, or a sloppy (i.e. obvious) repair of the gear would lower it's value greatly. Original but not functioning is worth much more than fixed! So, with that in mind, dad set to work. First he had to match the type and grain of the original wood. Several samples were obtained, and utilizing several hand-mixed stains, test pieces were made. I think the final choice was black walnut. Next, the broken gear had to be cut to allow the new tooth to be inserted. The tooth was carefully shaped by hand until it was a perfect profile. After that, glue was mixed with stain and the tooth glued in place. Careful sanding, staining and varnishing was done to match the original finish, blackened with age. The clock was timed, and worked perfectly. Even knowing where the repair was done, afterwards it was almost impossible to find. The now functional clock was returned, along with the bill. I think it was for something like $150, and my dad felt a bit guilty charging that much.
Imagine his surprise when, several days later the man showed up in person to hand my father a stack of $100 bills. Seems he had gone and had the clock reappraised. The value had almost trippled, and he showed his appreciation for the fine work by paying the bill 10 times over. That was a dozen years ago, and he still brags about it.