To repeat, Townsend for sure. Also Bob Wier. It's almost an artificial distinction between lead and rhythm. There's usually this division of labor if 2 guitars are playing together, but it seems to me that most of us are playing both at some time in any given song. And in some ways, it's harder to play really good rhythm chops...much easier to mess up by overplaying, etc. Anyway, most great lead players got there via rhythm, and they're usually wonderful at both.