The only way it is going 2 get hacked, is by installing a modchip, or playing around with the hardware.
I couldn't agree more... not that this matters but the PSX and PS2 needed to be hacked via a chip (hardware mod) - granted they were not as sophisticated as the PS3 (or XBox360 for that matter). I just hope we see a chip before the novelty wears off and a new system comes out!
Downgrading wont work after 2.10. It is assumed that there is either a version flag or a revocation field inside syscon (or another writeable area) which prevent from downgrading.
My personal theory is that there is a revocation area inside syscon (most likely some certificate) which is updated everytime you update and will prevent an old coreos from running unless it is not added in the revocation certificate (which should be the case of debug core os and ones used for servicing purposes, though I expect all the ones from retail updates to be added)
AFAIK only the original PS3 60Gb could play PS2 games - the other PS3 phat models (40Gb, 80Gb etc) cannot play PS2 games.
It seems the PS2 emulation was hardware based as the 60Gb also had 4 USB and a flash memory reader which is different from the later models.