It's definately not him. But the connection is interesting. He is currently filming BSG on the very same lot as Smallville. However, in the BSG blogs, he made it pretty clear that he would not cut his hair. And seeing that MMH is bald, it can't be him.
however, I'd love to say, that if Smallville had realized that he had been hired on Battlestar, that he would have been very available for some short guest star appearances, seeing that he is temporarily living in vancouver fro his stint on Battlestar.
and besides, he's already Mantis