actually the PS3 had full backwards capability with the OG versions in 2006. my first PS3 was fully backwards compatible. and to be honest, I RARELY even used that feature. by the time my OG PS3 got the YLOD, I didn't really even care anymore about no longer having the feature.
I used the fukk out of the backwards compatible on my fat 80 GB PS3. Used it for DMC3, Resident Evil 4, Capcom vs SNK 2 and Persona 3 and 4.