Have you ever heard of electrolytic rust removal? Check out this site. I have not used this process but it looks good and it sure would be cheap.
Picklex makes another product:
So does Zero Rust: www.zerorust.COM
Ultra One also makes a product:
I haven't tried any of these products but they have been talked about on various boards and the users praise them.
For the little bit of derusting you have I would just go ahead and use naval jelly. Buy locally and not have to wait for shipping and no extra shipping charges.