I normally use WASC cake or a chocolate version of it if I am going to be carving a cake but the customer wants red velvet cake. Does anyone know how I can either doctor a cake mix to make it more durable for carving or a WASC type scratch version?

BlakesCakes Red Velvet Redux - Easy and Durable:

http://cakecentral.com/recipe/red-velvet-redux-easy-durable

The secrets of cake carving:

http://cakecentral.com/modules.php?name=Forums&file=viewtopic&t=59361&highlight=carved

HTH