What about an Australorp cross?? I thought I remembered reading that an Australorp set the egg laying record. http://www.mcmurrayhatchery.com/black_australorps.html
My Australorps are wonderful birds. They are friendly, they stay in the yard...
You know the Brown Leghorns are beautiful..... Somebody brought one to one of our chicken meet ups. Gorgeous bird, and I would assume it has similar laying qualities to the white Leghorn, but a bit less "common".