There was a German TV crew at Insurgence. They interviewed Michael, asked about Smallville and got this quote:
Michael: "You know that's a tough question. I don't know. We've tried to work things out. I don't know if they're going to work out. Maybe they will, maybe they won't. I never say "no" to anything. I don't, you know? I'm open. It just has to work out right. It has to be right. So if that happens...I miss the guys. I miss the crew and cast. I had a great time. I was there for 7 years. A lot of people don't realize but it was 7 years. You know, I thought I was finished, but who knows? You never know."
Here's the video but be warned - if you open it in firefox, it will crash. Must be opened in IE. Features lots of Michael-cuteness: hoisting babies, flirting in German and a nice clear view of him talking about Tom's "courtship":