The Official Compilation of BWE Grievances.

[Nemeon Lion]

But do you need to update every rune to sup, or is sup something you can only have one of?

I think you need to update every rune to sup. I can't see anything that says otherwise.

[Alaris]

Actually, I did find evidence that sup runes DO stack, so yeah, you could wear 6 sup runes.
http://wiki.guildwars2.com/wiki/Runes

Now I want to know whether these pieces come with the rune included or not...