We have dealt with the same issue on the pilot-house truck forum and have experienced the same results as those listed above. Steele rubber really does seem to be the best fit. Now, having said that, we have had users that have had good experiences with Clesters:
http://www.clestersauto.com/index.htm
Their rubber fit properly and was a little bit less expensive than Steel's. They are a smaller company and don't have as large of an inventory, but I think you will be happy with their product. So far, they're the only alternative to Steel that some of us truck guys seem to be happy with.