You may remember Gaeowyn, the Rogue from Shards of Existence who tanked Mother Shahraz thanks to an insane amount of dodge via agility. She's struck again, this time taking down Gruul with herself tanking, along with a Paladin (with Blessing of Kings), a Shaman (with Grace of Air), a Hunter with Scorpid
pet Sting, ad a Druid (using Insect Swarm in addition to Mark of the Wild, of course). After all the buffs and debuffs, she had 76.31% dodge, 12.16% parry, and 14.16% chance to be missed, resulting in 102.63% avoidance. She posted a link to her spec and gear for tank mode, too. The video's short, but it took them a little over 23 minutes to down him. They also got to discover that his Growth caps out at a 30-stack, and that it expires after 5 minutes.
Considering the previous Gruul record was an 8 man, and that group used an actual Protection Warrior tank, I'd say this was a pretty staggering achievement. What's even more staggering is that Gaeowyn says she's tanked Reliquary of Souls, Bloodboil, Magtheridon, and even (as was teased at the end of the Shahraz video) Illidan. She plans to make an Illidan video pretty soon too, so we'll definitely be looking forward to that.
I'd imagine Gaeowyn's boss tanking has taken a lot of planning and setup, and it's awesome to see it in action, and she how people can stretch the limits of the game. I just hope my Death Knight doesn't get turned away from tanking dungeon runs in favor of a rogue come WoTLK!