"Wal-Mart will increase the number of Redbox DVD rental units from 800 to more than 3,000 over the next 12 to 18 months. Wal-Mart will also install 2,000 coin-counting machines in the superstores, to go along with the current 400."

This came from here which is actually more about the stock of the company.

They have a machine finder on their site. None of my local WallyWorlds have them but I'll keep checking.
The more the merrier.

Could it be possible that we might see coin counters in Canada finally? Time to email Walmart Canada and put in my two cents. (sorry, no pun intended).