I am planning on making the 3D helmet cake (Steelers) and was wondering if anyone could tell me the best cake recipe to use, that will be dense enough to support the layers? Does anyone have a favorite filling that will go with the cake? Thank you

Link to all the CC doctored/extended recipes:
(WASC and 3D durable are popular for carving.)

http://www.cakecentral.com/cake-decorating-ftopict-614378-.html

I generally use the sleeved pastry fillings...

Info on sleeved pastry fillings, as well as frosting/fondant recipes (includes cake construction & decorating help) follows:

http://www.cakecentral.com/cake-decorating-ftopict-605188-.html

HTH

HTH