Mike Long use to have a video on his website that showed bass going to town on trout freshly stocked. The bass would show up days before the truck came and would just wait.
Looks like he is charging for his videos now, but you can watch the preview of his big bass video. He's got a lot of great info on swimbaits and fishing in general on his site, its worth checking out. Here's the trailor, so yes bass eat stocked trout.
http://vimeo.com/ondemand/2261
I would think that bodies of water that get stocked with trout do have larger bass. A trout is a lot of protein and easier to swallow than something like a bluegill. If your thinking about trout swimbaits don't forgot about our spring friend the herring too.