The hardest part is getting the bait to swim. Anybody can make a plug that looks pretty but if it doesn't swim then it's worthless. As a matter of fact, I was admiring some of the wood carving booths at the hall show and wondering if they could make a plug... haha. The round plugs are pretty easy to make. I'd say make one with a bill rather than ac plug style because it will probably swim better. If you're not spinning it on a lathe or rod machine be sure to take equal amounts of wood off of all sides and sand it as you go. It's easier to tell the shape of the plug if you carve some with the knife, then sand it down and see what needs to be fixed, then go back with the knife and sand it down some more.
-Brian