I found this manual embossing machine: Cuttlebug
However, manually embossing would take too long for my purposes. Can anyone recommend an automatic machine?
As with most things, it comes down to costs.
You can hire a print provider to emboss for you. They have big automated machines to emboss thousands of sheets quickly.
If you don't want to pay for that, then you are limited in your ability to improve upon the time necessary for manual embossing.