You really only need 3 TPIC6B595 shift registers.
Each output can sink 15mA from up to a 50V source.
I have this little board with 3 of them and Arduino functionality.
I can send a bootloaded kit for $25, plus $5.25 shipping, and 2.39% paypal fee.
Connect +12V to Vin via barrel jack, Vin on headers goes to + on RGB strips, - on the 8 strips go to the header pins.
