What about an iced chocolate or red velvet cake with pirouette cookies edging the outside of the cake, then tied with a festive Christmas bow? Or
tiramisu cake - I used to make this a lot for my boss who was a huge tiramisu fan and it got rave reviews.
Here is a link with some additional ideas. I think the chocolate-gingerbread-toffee cake and the cranberry obsession snow cake look great!