r.colors: make nice random colors like r.watershed
r.watershed has some color rule creation code it in which makes the random rules not quite pastel in nature, but cool. it's a lot more pleasant than r.color's color=random method.
see the r.watershed examples here:
it would be nice to move that rule generation code into libgis and then add a new "r.colors color=random_cool" or similar option. (and simplify r.watershed in the process)
My preference is that the seed would not be constant by default, so if you don't like the result you just run r.colors again and d.redraw.