You're all busy trying to find exploits in the bios or possibly games...
... you could engineer one yourself.
now stay with me on this one: :Cry:
1) write a cutesy puzzle game (reasonably easy thing to do)
1b) ensure there are numerous backdoors in the coding
2) get it published <---- the tricky part
3) once released it'll be signed by $ony and, of course, fully exploitable
now 2 might be a tall order... but if you consider the economics of the situation it might even be possible to setup a software co. purely to do this.
Lets face it if your game is the one that can allow homebrew to run, it'll sell, regardless of the game quality, meaning you're prolly gonna make money on the deal anyway..
ok this is rather far-fetched, but hey it *is* possible. people start companies, sell games and do reasonably well out of it.
...righty-ho back to reality I guess...