I'll have to go back to the store. I thought the FZ3 was the same size as the Canon if you take the hood and adapter off. You might want to check out the www.dpreview.com
review of the FZ-3 it directly compares the cannon and the Fz-3. There are trade offs (no manual focus, less capable movie mode) but I think the resolving power is better and it does a better job of focusing at low light.
But they are your pants that it has to fit in.