Wow, this looks fantastic!
I have only skim read it but it look great and ideal for one of my current projects.
The constant current feature is great, no more wiring up fiddly resistors!
I do have one quick question. Will I be able to wire four identical ~3v LEDs in parallel from one output without using resistors?
The flash storage feature is fantastic too. This will mean it can be used in projects where the PC is not always on or where there isn't a PC at all!
Damn, I have some serious thinking to do now.