Reply #2: Colored chocolate

[supernova]

You can find colored white chocolate discs at a craft store like Michael's or A C Moore, though the selection tends toward the seasonal ( red and green at xmas, red and pink for Valentines, for example -- may be exactly what you are looking for).

If you have any sort of specialty food shop, they may also have paste colors in small vials. You can have a lot of fun with that. Remember a little, meaning a drop or two in a batch, may be enough to achieve the effect you want.