I remember someone on these forums showing how they made digital camo by using salt and an AB... can't remember who or when though. Basically paint the base color, add salt grains while still tacky and let dry. Overspray in small areas with color #2, add salt grains while still tacky and let dry. Shoot color #3 and rinse and repeat. Once dry, remove salt. Should work well if done right.
If DCU, I got nothing. Sorry.