Last week, a video surfaced showing a Druid, Serennia, soloing Onyxia. There was some controversy as to whether this was actually a 'solo' kill since a hunter was inside the instance at the same time.
Last night during our MC run, Aeth told me about a Paladin, Par, doing the same thing, only this time truly solo. The video is really long, nearly 2 hours, but its a legit kill. He said the first time he did it, which wasn't recorded, took him over 3 hours. Crazy.
I love to see things like this. I have perfected the 45-Minute Baron Run, tried ZG solo, and so on. I am actually looking forward to WotLK, so I can try things like MC solo.