There isn't one.
Legend just happens to be the only one of the four major units (aside from Destiny, SF and IJ) from GSD that never had a MG. That said, I think it's too unpopular to get a MG?
Yeah, it does have a bunch of strikes against it.
1) Nothing more than a rehash of the Providence Gundam
2) Piloted by a rather disliked character
3) Veeeery little screen time compared to the rest
It really only existed to hammer home the whole "Ray = Rau" bit. Which was effective for all of thirty seconds before Kira blew it up. The others not only had better animate effects, but the Infinite Justice and Destiny also got all the screen time from Athrun scolding Shinn.
