I could always just do bits of it coloured, but then that'll take a lot more planning, and I'm not sure which colours work best. I've tried doing rainbow colours (red on the outside, violet on the inside -- though actually I wonder if that wouldn't work better the other way round) and other combinations of colours (red, orange and yellow -- which works quite well but I think will look a bit crap just on its own; green and yellow which doesn't work too well, and blue and purple which doesn't work as well as I thought it would).
I think part of the problem is I'm used to doing this sort of thing on cakes and on a cake it doesn't sit around accusing you for as long -- telling you how much time and money you wasted on something that looks shit -- if it doesn't come out right.
Advice welcomed on which sort of thing might look better, or whether it'd be better to just leave it white.
Photos supplied (which haven't come out very well but they're the best I can do with my crap camera).