Strong,
I have read that several modelers use Rustoleum paint and claim it is fuel-proof. I beg to differ, depending on your nitro content!
I did a test and found that 25% nitro will eat through it!! You can use some cheaper spray-bombs and then clear coat with Lustre Kote, but it is only good to 15% nitro. For true fuel-proof applications with higher nitro, use a two-part automotive paint or K&B epoxy paint (available at www.modelengine.com).