I did a bit of work on a wee arduino project to implement presets on a Darkglass Vintage clone. I was really trying to see if I could improve on the implementation of the Tech21 preset functionality I'd seen in the VT bass deluxe I owned. Which was stinky poo... Not the sound, but the fact the position of the controls bore no resemblance to the actual preset settings! Having played around a bit I can see why it was done the way it was, but I wouldn't buy another pedal with that sort of preset implementation.
As with many of my projects, I didn't get it finished, but I did enough to know while it's not difficult to do, I doubt my implementation, or anything like it, would be good enough for Doug's asthetic vision for Darkglass products. It's not in the same league of difficulty as what DG have implemented with their DSP work (it's probably around the same order of difficulty as the workings of their intelligent footswitches for their amps).
I got as far as storing 3 different presets and recalling these values to a quad digital potentiometer. The issue is the design of the user interface. I was happy enough to implement mine with a single rotary control with integrated push button, a little 0.96" OLED display for indication of settings, 2 footswitches and 4 LEDs.