Well folks- here's the newest design.It features Analog Maximum Current adjust-ability and PWM dimming. I designed this on to operate off a 48 Vdc supply and output up to 4.5 amps. I'm sure (with the proper fuses and load balanced led strings) this little driver could run 48 XPG's at 1000ma (4 strings x 12 ) or 1 string of 12 XML's at 3000 ma. Not too shabby- IMHO, for a driver that costs around $20 to build. I'll post up the EAGLE files and a BOM if anyone's interested in building their own.