Try befriending someone who works in the produce section of your local grocery store (smaller, privately owned is probably your best bet.) I have worked in produce for years, and can attest to how much good stuff is just thrown into the trash. I take home at least two boxes of trimmings from organic greens, and bags of corn husks everyday, as well as the occasional box of pineapple tops.
I know it's not woodchips, but ask if they would be willing to save a banana box or two for you, or better yet a whole garbage bag. Just make sure you pick it up promptly
