the 13 inch MBP will definitely stay. I go to Penn State. WE ARE......PENN STATE! and i cant tell you how many rich sorority girls or any daddys girl have the 13 inch macbook pro. It took alot of business away from the regular white macbook with just about the same specs but $200 bucks more. Its an easy way to make more money for apple. Who would want a white macbook when they could have a shinny aluminum case? Whether it gets an internal update is all in the hands of jobs replacement.
well i prefer the white, it doesnt bent like the aluminium and the aluminium cuts your fingers if you spend a lot of time on the computer. oh and its more expensive with only things provided firewire (which very few people use compared to usb), and backlit keyboard (which is good, but since the macbook's keyboard is white, the screen lights it enough).
oh and also, the white macbook has a significantly better wifi signal
About the keynote or not, i believe if the macbook air is truely "the future of macbooks" and they're making big changes on the next gen pros, they'll have an event about it. if its just a spec upgrade like sandy bridge cpus, it will be a store update without notice.