Dynamically dimming individual LEDs in a lighting system
To answer your question about current regulation, a handy feature of LEDs is that the forward voltage across them is approximately constant, regardless of the current.  So a red LED drops about 1.5V, a blue LED about 3V, and the other colours are in between.

Knowing that, it's possible to use a simple resistor to limit the current through the LED to a suitable value.  The resistor value will depend on the supply voltage.  If the supply voltage is well above the voltage of one LED, consider wiring a few LEDs in series, otherwise you'll have to deal with a bunch of unnecessarily hot resistors.