I just finished doing a project that used an arduino to control 12 separate strips of LEDs with all sorts of different animation patterns to indicate the flow of water and gas on an exhibition model.
To save hours of wiring up LEDs to shift registers I searched for pre-built strips that are individually addressable and was surprised how hard it was to find them in the UK.
Eventually, I found a company called Logic Magic (http://www.logic-magic.co.uk/
) who have designed a board that is just 8mm wide and has as standard 3 banks of 8 LEDs. The boards can be cut into individual banks if required.
The boards can be populated with different coloured LEDs as required but need to be a single colour per board.
Each board only needs 4 arduino outputs to control all the LEDS and they can be daisychained so you could control a pattern across many LEDs from just 4 outputs.
The brightness can be set by PWM on one of the 4 connections.
I also understand that they are designing a board with RGB LEDs so that much more sophisticated animation would be possible.
I know it sounds like a shameless plug but I was so surprised how hard it was to find these things I thought other arduino users might appreciate the tip.
Let me know if you have found any other alternatives.