Excellent, thanks for sharing this. I'm going to be getting some STP04CM05 4-bit shift-register/high current LED drivers in the mail soon, and will try to adapt this code for that application. They also feature cascading so I'm guessing the only trick will be changing any 8-bit references in the code to 4-bits instead.
If this works I will be saving a lot of $ on hardware and a lot of head-banging on circuit design! Before I found the STP04CM05 the only cost-effective solution was a slew of TI PWM multiplexers, hex converters, transistors, and current regulators.
I will definitely buy you a beer in that case. 