Didn't Sony just pass a patent for a PS2 software emulator that can run on the Cell? It'd be useful, because the older PS3s that do emulate on software, can only play certain titles. Giving them a better emulator would resolve all those problem. Now, if they kept this new emulator to the slim version only, then I'd be upset. That, or if they charged money for it.
Regardless, every PS3 can already play PS1 games, so technically, every PS3 is backwards compatible, just not in the way some people want.