One things for sure, there will be no punches avoided in this one. It'd be fun though. I think Harding batters Lacy though. Bigger, stronger, more durable, and just plain better.
Not to be one of those retrospective guys, but I didn't even watch Calzaghe-Lacy live, I was so sure of the outcome. I just never got the hype surrounding him, in fact I was surprised it was seen as such a big deal at the time. I say this as one of the biggest Calzaghe fans on this site. Harding wins this comfortably imo.