The post in the op only compares the GPUs when, as i'm sure you know, the Cell can be very effective at pre-processing in order to aid the GPU. This throws things out of balance and thus 'on paper' comparisons really can't be used as the systems process graphics in a very different manner. Yes talented devs are incredibly important, but i wouldn't say the 360 is certainly more powerful at graphics processing, in truth i bet no one really knows which has the greatest capabilities.
No one really knows the answer to that, as i stated above the two systems work in very different ways so to say 'yep, the 360 could definitely do that' just isn't possible. I'd wager it could though.