[mmm_grayons]

I've tried it a few times on my kindle, and it sounds like a nice things to have. However, the screen's refresh rate is crazy low. I'm guessing that can be improved, but that would likely come with a battery life hit. More importantly, good luck scrolling on a webpage where it takes you a second to see how far you've scrolled. Same issue were you to respond to a comment: typing with that sort of latency is absolutely dreadful. E-ink works great for displaying text and is so much better for reading than a screen, but there's definitely some more technological work to be done first.

[Wowfunhappy]

I'd expect to be using the equivalent of page-up/page-down buttons to scroll through sites.

I wouldn't expect to be typing on it—but, I've absolutely seen e-ink screens that can refresh quickly enough for typing. They start artifacting a bit when you force them to refresh quickly—which lessens the contrast advantage—but then they fix themselves once the screen has a moment to "refresh" itself.

[int_19h]

Just as you've said, it's a battery life / refresh rate trade-off. Dasung makes some e-ink tablets and external displays that have a dedicated hardware button to switch between various modes - in "fast mode", it's good enough to type text and use the mouse. But, of course, don't expect anything like Kindle battery life.