i wouldn't have a problem doing this privately for home use in a pressure canner. i honestly think it'd be pretty safe if you processed it for long enough; a lot of the rules about what's "not allowed" aren't at all because they're unsafe as much as because there hasn't been sufficient and legitimate testing done on it. with that said, i don't think i'd take a risk on a professionally sold product without explicit approval and i'm betting (though i'd love to be wrong) that your local authorities aren't going to allow it.
i like @pastrygirl's idea about just selling it as a refrigerated product. consumers have experience with this sort of thing anyway and i don't think anyone would bat an eye, to be honest. you could also investigate cooking the caramel and adding a preservative to it. less label friendly, perhaps, but i'm skeptical it's something most people are going to care about.
