High Power LED strand Power Supply
Power supplies for LED's have come a long way. There are constant VOLTAGE power supplies, and constant CURRENT power supplies. LED's like constant current. What you mention is probably the "optimum voltage/current" for the LED. Since voltage and current are related to each other you can get away with more than one or the other. (For example running 24 Volts at 3amps = 72W). That being said there are now lots of power supplies that will take 115VAC and convert it to low power steady DC.. They are called "LED DRIVERS".. Ebay has tons of them.. Yes alot of manufacturers are in china but with some digging on Ebay, you can find an american supplier. Search for "CONSTANT CURRENT LED DRIVER" and find one that matches your specs.. they can be had for cheap.

6.7A 12 Volt DC Power Supply