(from the Aha! So *that's* what it looks like! department)
Just a quick digaram of the internals of the PS3. Original article here. (Translation)
Also, as a follow-up to my prior post, if you translate the original article, you find this tidbit of information about the original EE-less design constraints:
(Note: I've smoothed out the auto translator "english" a little. It should be pretty close to the original Japanese, although this is *not* a direct translation.)
"According to an industry insider, the GS was retained because it can't be emulated by the PS3 chipset. This is due to the GS's pipeline architecture which requires 4MB of super-wideband and low latency eDRAM. Because the RSX (Reality Synthesizer) GPU of the PS3 has a PC graphics pipeline with external memory, it can't replicate the special architecture of the GS."
"Moreover, it is difficult for the cluster of SPUs (Synergistic Processor Unit) in the PS3's Cell BE processor to emulate the GS. Even though each SPU has 256KB of on-chip memory (Local Store), that is insufficient for the requirements of the GS. In addition, a number of game industry insiders point out that there are many developers who did direct, custom access to the GS which would necessitate a hardware solution."
So, based on this, it looks like these 40 gig PS3s are going to remain incompatible with the PS2 - for the foreseeable future, anyway. I'll keep you posted if Sony changes their mind, but at this point, I think it's fairly safe to say that PS2 emulation has been eliminated from the PS3.