Does it need to be that complicated? Just get a wall adapter and use the proper resistor to limit the current. I'm currently building a 600 LED array for Stealth Web Designs (their new sign) using a simple 48V power supply.
If your LEDs drop 3.5 volts and have a 30mA max rating, and you have a 12V adapter:
3 LEDs x 3.5V = 10.5V
12V - 10.5V = 1.5V
30mA = 1.5V / R, R = 50 ohms (47 ohms is a common resistor)
So you will have 3 LEDs and a 47 ohm resistor in series, and you can parallel as many of those as you need. The wall adapter needs to be able to supply 30mA x #series.
Here's a simple way to visualize it: http://led.linear1.org/led.wiz