How about this idea???

Instead of a "cap" over the sheared riser, that is allowing for at least 30-40% of the oil to still leak out into the Gulf), what if a large diameter tube/sleeve was made that would go around the BOP (weighted around the bottom "rim") that would channel the oil to the surface to a much more concentrated area that could be burned at the surface?

As it stands now, the oil is so diffused by the time that it gets to the surface that you can only burn by collecting at the surface. The way to think about it is dropping an Alka Seltzer into a swming pool, versus into a tall glass. The bubbles will be very dispersed by the time it gets to the pool's surface, but limited to any "spread" in the glass.

Just a thought.