Richodemus points us to Blizzard’s Runestones page, where something is afoot. The runes are now sorted one per difficulty level, with 1-4 corresponding to Numpty/Nightmare/Hell/Inferno… and then 5-7 are off to the right, as if they exist in some post-Inferno state.
What might this indicate? Rune levels 5-7 are being removed from the game? They’re not findable and can only be obtained by crafting with Inferno reagents? They’re earned in rewards or achievements outside of the normal gameplay? (Imagine that the Runes level up in some way once they’re socketedf? So you’d only be able to trade up to rune level 4, and to get to 5-7 you’d have to socket a rune and do something to upgrade it?)
We still don’t know what’s going on with the whole rune attuning system either, but thankfully, we shouldn’t have to wait too long to find out. In just six days the second Diablo III panel at Blizzcon 2011 covers the, “Skill, Passive, and Runestone system.” All will be revealed! Assuming the developers have actually settled on a final system at this point. (Which I would *not* bet a lot of money on.)