They haven't even figured out how to completely emulate the PS2 GPU on computers that are more powerful than a PS3. They are still in 0.97 beta with a lot to work out (not to say they haven't done some amazing work thus far). Not to mention, it took them several years and the people doing it are not involved with Sony. Therefore, Sony would have to do all the work from scratch, and design it to fit within the specs of a PS3.
If it could be done, it would not be seen until PS4 was out. The best they can do now is try to design PS4 to be able to run PS3 games without additional hardware. PS2...well, I guess if they think it's financially feasible to put the PS2 hardware into the PS4 like they had in the BC PS3s, then more power to them.
Or were you talking more like putting the hardware for backwards compatibility back into the new PS3 slims? The ones that restrict Blu-Ray movie playing? That could work. They might still be able to offer it at a fair price.
Demon's Souls/Dark Souls Stat and Weapon Calcs http://sites.google.com/site/darksoulstats/