1. Blur filter is only available on WebKit
2. I know for sure how much texture memory is on an iPhone 5
3. The touch event latency on android is too damn high.
I do synthetic scrolling (translate3d() + touch event interpretation and inertial math). Then duplicate the DOM for the top and bottom bars, adjust the positioning to make them look fluid and apply the CSS blur filter.
It looks better when you see it moving.