IMHO I don't think an unhappy ex-Apple coder would cut it. I would consider myself to be a reasonably talented programmer with a good understanding of a number of languages (modest too!), but I don't have 1/10 of the skill necessary to put together code which would exploit the operating system in all the ways that would be necessary to do this.
It's nothing like writing a "nasty" app. It's a whole different ballgame with completely different rules, thanks mainly to the way Apple protect their devices.
