Interesting to note that the SWTOR site now has 8 classes.
Looks like 4 per side may be a reality.
Here's my speculation
Sith<- referenced enough times likely to be a class
StormTrooper?(mentioned in the gamespot interview as a class)
medic?<- pure speculation
Jedi<- referenced enough times likely to be a class
Smuggler(official now as it has it's own class forum and they only like mentioned the smuggler class like 8000 times in all the interviews for E3)
Doctor?<- pure speculation
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson