Apache::Reload looks like it will do what you want.

If I were in a similar situation, though, I wouldn't use it for two reasons. First, I prefer to catch my mistakes by writing tests before I write the code. Second, because I'd probably use the fake Apache module on the CPAN. (I can't remember its name right now.) I've developed by stopping and restarting Apache and mod_perl, and it bores me. I want faster feedback. :)