HinderRust seems to get some good reviews; I haven't used it myself but it was developed by the inventor of Tufoil, which I swear by. http://www.hinderrust.com/

As noted above, rust is an oxidative process. It is not a living thing like cancer which will no longer grow if completely removed, it will grow on its own given the right conditions. Keep the oxygen away and it will not grow. Existing rust does not spawn rust, oxygen and iron does. Water and salts will hasten the process.