As you can tell from the list, it's sort of hard NOT to find pressed penny machines. Our family just got back from WDW and the kids LOVED doing the penny machines. We only allowed them to choose 1 design in the machines where there are 3 offered and they each still ended up with 20 pennies.
Here's a really good suggestion that we had read on these boards somewhere and we used on our trip. Before your trip, buy a package or two of m&m minis that come in the tubes. Then fill it up with 2 quarters/1 shiney penny, 2 quarters/1 shiney penny, 2/1, 2/1, 2/1, got it? That way you don't waste time searching for quarters and pennies. You could also do 1 tube per collector and when it's gone, it's gone.
I will warn you though, we enjoyed the pressed pennies so much that we had to refill our money tube a couple of times.
Also, when going through the airport on the way down, the money tube was in my backpack and they opened the backpack to verify that it was just money. Afraid to even think what it looks like.
Have fun with your pennies!!!