I've been looking everywhere for the files to print my own watch case for the Smart Watch. Where can I find them?

You may wish to just design your own. Since the Smart Watch kit came out, Tiny Circuits released the Tinyscreen+ which has the USB port built in. This is a huge improvement over the original smart watch since the old had to be removed from the case to add in the USB board for charging. Just food for thought.

I think there used to be a link from the tutorial, but I'm not finding it there any more. A little searching led me here:

https://sketchfab.com/search?q=tinyscreen&type=models

I believe you have to sign up for sketchfab in order to download. I know I had to way back when. I tried printing it once, and found it somewhat unsatisfactory, so I ended up ordering one from TinyCircuits.