Hi I would make 3 cakes. One say 10" or 8" for the tummy an 6" for the head then a square cake to make up the other bits cut a little triangle for the nose there will be a bit of cake to join the head to body and then cut the tail shape, cut a a bit for the raised cheek. The rest like ears would be gumpaste. slightly round the edges of your cakes with knife. Cover the lot in butter cream to fill in all the gaps. Hope this helps good luck.
Elizabeth Miles Cake Design