A large number of popular apps in the iPhone App Store have the ability to receive code remotely and execute it. I think this is especially common for games that will often use a scripting language to implement the game and then will push soft updates using the scripting language. But:

1) do you think apple limits what functions these scripting languages can access? 2) do you think apple audits the scripting language to ensure it cannot execute native code via an exploit? for example a lot of Lua runtimes are 'broken' and its trivial to get native code execution.