This birthday cake idea was made from an 8" round (4" high), and a piece of cardboard. From there, I sculpted the slope on the backside or the hat free hand. I choose to use fondant on the outside because it gave the cake a realistic, smooth finish; opposed to using butter cream (If you decide to go with butter cream or a whipped topping, be sure to use a CRUMB-COAT on the cake prior to applying the final cover of frosting!)
To make the "camo" fondant I just took pieces of different size/color fondant and smashed them together before rolling the fondant out to fit the cake. After the fondant was placed on the cake, I simply made a "hat bill" from cardboard that fit the cake and covered it in the same fondant.
Once you have the cake frosted/covered you can customize it for any team or logo.