Actually, I remember reading about how hackers discovered a loophole in the PS3's "other OS" hypervisor. Xorg developers were able to directly access the RSX graphics hardware and proceed to develop a driver with DRI support.. However, Sony later patched the loophole in a firmware update.
As W3bbo points out... the latest slim-line PS3 doesn't have the hypervisor any longer. Not only that but so much functionality is stripped from the latest generation PS3--backwards compatability is the big one.
I have the original 60GB PS3 and its plays my PS2 games like a charm with the integrated emotion engine and other hardware. I could just upgrade the HDD in my original model and it would triumph the latest generation PS3.