Following Irene's recipe, I did this piece last week. All photos here are from different areas on the same half yard of muslin.
The key to getting outrageous prints from rusting is this ~ soak your fabric in 50/50 vinegar and water, til the fabric is really wet. Wring out as little as possible. Wrap the fabric entirely around a rusted object, over and over again until you've got a neat little package that's really wet. Wrap this in clear plastic, a baggie if it'll fit, then wrap that in another piece of clear plastic. Let "cook" for 4 or 5 days. Unwrap, wash out in cold water, then wash in hot water with synthrapol.
I haven't figured out how to do this, yet, with a very large rusted thing. But maybe it's not necessary to have big objects when you can get full coverage on a piece of fabric with this method.
If you're interested in seeing Irene's photos, email me and I will put you in touch with her. She doesn't have a web presence and I'd prefer not to list her email here. But I'm sure she'd be glad to share her work with you!