Oh, well, that's different than a gyros. I've never seen one here that has ground meat in it. Small cubes (like maybe a quarter inch) to sizable hunks (maybe like and inch and a half by an inch by half an inch) would be much more common. On the other hand, I almost always get the chicken and not the meat-on-a-stick (which I think is reconstituted ground beef and lamb) -- I think that's shwarma -- but I think it's still served in similarly sized chunks to the chicken.

Oh, wait. Maybe you were describing the shwarma. It's not loose ground meat in the sandwich, right, but cut into chunks?