I would think that the PS3 supports more than just ES, as Unigine has been offering their engine for use on the console, and their benchmarks using said engine use the latest OpenGL 4 features like HW tesselation (http://unigine.com).
I don't know what the story is exactly (I quit my job at a major UK developer shortly before I was supposed to start working on a PS3 project) but there are some details here: http://en.wikipedia.org/wiki/PSGL
Since RSX is rumoured to not be that powerful, I suspect Unigine might be doing the tesselation on the Cell's SPUs.