Try doing a search on novelty quilt fabric or novelty quilt panels. I have found several out there, by just doing a google search. This is a really good one but their are many. Also do a search for a specific type of panel. I did one for a quilt called gone fishing and actually found a panel that said Gone Fishing.
http://www.jandofabrics.com/Fabric.a...%3aKeywords%3a