I love Sonar, and have been a lifetime Cakewalk user, and wouldn't switch to a Mac if someone paid for me to, but having said all of that... I really don't think Mac people are waiting around for Sonar to be ported. They all think their options are better than Sonar anyway. It's like a snobby thing. I of course think Sonar is the best DAW, but I don't think any of them are waiting around for it... Which makes me think the big announcement being Sonar for Mac would be silly. But again, with THAT being said, I can see how anything that gets more people using it can be an overall better thing for the product and brand.
But with all THAT being said, I doubt it, and we'll know tomorrow :-)