I e-mailed Wilton about this a while back. It's a no go. You can't sell copyrighted character cakes made with Wilton Pans. They say it's because the companies can't control the quality of the product/representation. The only character cakes that can be sold are the one's like Walmart sells. These are sheet cakes that use kits. Even these have to be presented in a certain way. Some Wilton pans even say that they are for home/personal use only or that they are not to be used for commercial purposes.
OK- major research done by me here. I have posted on this many times. I just recently re-researched and have updated info:
You may not create or model any cake after a licensed character without express written permission from the company. You may use the plastic figures, approved edible images (sold by the company - not ones you printed at home) toys and other such items legally for the selling of your cakes.
Straight from the Disney site:
No material from any WDIG Site or any Internet site owned, operated, licensed, or controlled by us may be copied, reproduced, republished, uploaded, posted, transmitted, or distributed in any way, except that you may download one copy of the materials on any single computer for your personal, noncommercial home use only, provided that (i) you keep intact all copyright and other proprietary notices, (ii) you make no modifications to the materials, (iii) you do not use the materials in a manner that suggests an association with any of our products, services, or brands, and (iv) you do not download quantities of materials to a database that can be used to avoid future downloads from any WDIG Site. The use of any WDIG material on any other Web site or computer environment is prohibited.
Most companies operate the same way.
Until November 2003, you were not even allowed to do it once for home use. But this has been changed as you can see, as long as you follow their rules.
HTH!! 
I also heard from a lawyer friend that the big companies that hold the rights to the character wont go after the little man that it would cost more then what they would get (if they would) if they won. The company would take things like making a cake for someone in the form of their character word of mouth for their products. Think about it, I know when my boys are invited to a bday party and the invitation is say Yugioh, power rangers etc, I go and look to buy a present with that character on it.
Now I have heard of a company going after a wholesale club for use of their character without permission, because within a company like that it gets out and then the other warehouses get the idea and so on and so on. Then it is totally out of control!!!!
So though I am not legal person, or minded I feel us little people would be fine doing a cake with characters, just dont sell it for a million bucks! 
They do go after the little guys as time allows. Heartsease on Ladycakes site called Disney (yes, they will really talk to you when and if you get through). While it may not be often and even extremely rare... it does happen. You are taking a gamble every time you do this outside of their preset limits.
I'm not saying to do it or not. I've done things that stretch the limits of the law. But I'm choosing that gamble and I am fully responsible should I be charged. You just need to be aware so that you are making quality choices based on fact, not hear-say.
For those with ladycakes memberships, here's the link to that post. Read the entire thing. It is very interesting all the way to the end.
http://www.ladycakes.com/forum/showflat.php?Cat=&Number=236812&Main=234872#Post236812
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