Basically -[UIApplication openURL:] would be perfect, if it wasn't for the fact that it doesn't work within the same application (at least on simulator -- if this works on device someone please tell me). It's not a super big deal though if it just relaunches w/o URLness since I can obviously just persist some data. The goal of this is to essentially free all memory in the application and call all of the loading procedures.
You almost certainly could do this with the C library call execv. But like everybody else, I think it is wrong to even be thinking about it.