The 4 Queens had 12 machines, with 2 that gave out $40 gold caps. They were near a main aisle and they had 3 $10 types of tokens, but no colored caps.

I'm sure I paid $100 to get one.but the quest is fun! There were two at the Plaza, sort of in the middle of the casino near the back. Went looking for these machines after seeing this site, and had a ton of fun playing them! Payout was great on the $10 coins, and then just trade the duplicates in at the cashier for more money to keep trying! The $40 coins are much tougher to get.