Hacker News Reader

As an alternative, I'm going to start using something like http://emberjs.com/list-view/

(warning: not mobile optimized)

It solves 1, 2, 3, 4, 5, 7, and 10, and could reasonably be implemented with bookmarking to fix 6 and 9.

SEO is still an issue, but really, when is it not?

For SEO use the next link relation[0] e.g. <a rel="next" href="/resource?page={next_page_in_sequence}" />.

I am assuming more results are loaded based on scroll-depth < 100% + an overlay to stop the user clicking.

Google/bots will be able to activate the link and request the next set.