The next refresh is expected at the end of summer, together with Mountain Lion.
I don't think they'll do away with optical drives, it's one of the main differentiators between the Air and Pro lines. However, I'm pretty sure one thing we can expect in the next Pro lineup are Retina displays, maybe as an option first. SSDs are available already, as ridiculously-priced options; again, since they are base in the Airs, I expect them to stay optional in the Pros, at least in the lower-range models. Another thing that could happen is a sizeable battery capacity bump, after seeing what they've done with the new iPad (almost double the capacity of the old one at the same price and weight) - for Retina screens, that'd be very much needed.