Here's my snapshot from the other night.
Like I said previously, I thought the flare my just be caused by my filter. After reading this thread I'm 95% sure it's just the mirror box in the camera now. Not a big deal... I've never had this type of flare before in any image that really counted.
Thanks for posting, it's the familiar flare alright. It looks like there is a small spike in the snow on the road as well... At least it's confirmed it does not only occur with Sigma lenses, and given the right conditions, almost any lens can produce the effect on the 5D Mark II, at least those with a wide aperture.