There are quite a few exceptions, so don't worry if you don't look like Tony Robbins. You can wear costumes like the Indian Chief I mentioned above. I know one guy who dresses like a motorcycle gang member. Another lady dresses like the female version of Marco Polo. Then we have Clinton impersonators and a good friend of mine is a Madonna impersonator.
Packaging is critical to make lots of money speaking.
Unless you are already in a high profile position, the packaging is the way people get to see what you have to offer. There is a reason for this. People don't really buy books and tapes. They buy materials that will give them the knowledge they desire. It's no different from when you go to your local Home Depot to buy a book on building decks.