The Kindle 4's latest software revision, and the Kindle 5, support KF8, which has better table support among other things. The viewer is... suboptimal, though, as so far every single book I've viewed in that format has a different font size to all the others I own, so I'm always having to fiddle the font size to keep things the same apparent size. This is probably a bug which might possibly maybe be fixed (or maybe they've taken a leaf from the music biz and expect us to buy all our books again to get them in KF8 form!)