I also feel funny about using colours so I try to come up with themes that I can use mainly chocolate like teddy bears, construction sites etc.

My last cake though what I did was buy white choc which I melted and added a little of those Queen natural colours mentioned above and put them into choc moulds so I could makes flowers, teddies, letters whatever you can find a mould for. Then I just did basic white icing and put the decorations on top and thought that parents could easily pull off the chocolates before serving them to the kids and then they wouldn't have to eat them if the parents didn't want them to. Or you could do a variation on white, normal or dark choc for your decorations if you didn't want to use any colours.