Vince, your best bet would actually be to use a P2P network. A lot of times, people will capture commercials and make them available for download. There are a few newsgroups where you can get commercials as well, but P2P is the big one.
There are other alternatives, like Ad Critic, but get ready to pay just to get anywhere beyond the home page.
Little-known fact: The people who animated the Chevron cars and the Serta sheep are the Aardvark folks - the animators for the world-famous Wallace and Gromit.