The "Peter Chou" style power supply is available from the major coin op parts houses such as Happ Controls, Betson, Amusements Plus, and Competitive Products. You can buy online from them or if you're in their vicinity, stop by their offices and purchase over the counter. You can also buy them from the many coin operated machine distributors all over the country. Just look in the local telephone directory Yellow Pages under "Amusement Devices" for any companies with "distributing" in their name. Then you can buy them in person right at their parts counter.
You will definitely NOT find these at Radio Shack.