Could servo-shell be used to implement a keyboard driven browser (a la dwb)? Looking at https://developer.mozilla.org/en-US/docs/Web/API/Using_the_B... it looks like the API does only offer few interaction points with the underlying iframe or shouldn't that be a problem? Can the browser html intercept all key presses and change the iframe content to display follow links, for example? :)
That might be a great way to finally have a better keyboard driven solution (since, i think that the browser addons like pentadactyl suck very much).