PS3 emulation is kind of a hot topic, but even emu authors themselves admit that it's not feasible due to the sheer difference in architecture and because of how powerful the system is.
Sony is crappy with security but they're pretty good with proprietary hardware. The PCSX2 authors are having problems even with the PS2's VU chip because it's capable of pumping out texture in parallel, and in amounts (not speed) that would make even current videocards struggle if no hacks/shortcuts are used. Thankfully it's only used in rare cases (Final Fantasy XII, for instance, with Basch's mist attack at the end - even in low resolutions, the final part brings a GT 240 to single digit FPS)
It's been said that PS4 emulation would be more feasible than PS3 due to the similar architecture but even that is not possible with current hardware (in fact, the original Xbox doesn't have any actual playable emulator yet even though it's basically just an old PIII PC with a videocard that was considered midrange a decade ago. All they were able to do is a wrapper that translates function calls into DirectX ones, so it only works on a per game basis.)
