I experimented with red and blue base colours this year, but while I thought they photographed well, they actually didn't sell. I think people are quite traditional when it comes to Christmas cakes.
If you do sell your cakes at Christmas fayres, and haven't tried the smaller sizes, I would give them a try. There is almost as much work as in a large one, so you do have to price accordingly, but lots of people think they are the perfect small gift for an elderly neighbour or a gift for your children's teacher.
I think traditional Christmas cakes are so yummy and so pretty. Will post a selection from my next batch. Planning a cake free day tomorrow though!