If we want to push this any further, what about ... erm ... 1 color, 1 hour ? That's basically basecoationg and then ... oops 1 color used already ... finished !
No, honestly, I think, 4 hours are about the correct time to get something done and 4 colors also seem right. With 5 colors (blue, red, yellow, white, black) you
can do almost anything. 3 Colors seem a bit reduced. You need at lest 2 colors for highlights and shadows. And then there's only one real color left.
What we could do is restrict the model to paint. Everyone could do the same model or a basic rank and file trooper of any self chosen army.
What also comes to my mind would be an unusual light source. Not the standard zenithal light, but some light coming from left or right or from the feet on the mini (basically inverted zenithal light).
What do you think ?
Egrimm