Yeah, I was a little bummed about this one as well, considering how frakking cool the cockpit is! I wanted to see more of it!
Freelook at the moment only works with TrackIR which is a head tracking device. Freespace engine is pretty old and the free look options were pretty limited when the engine originally shipped. I'd like to get freelook working with the mouse someday but it's going to require some thinking to make it play right with how Freespace currently handles mouse options and such.
Perhaps, some kind of Shift/Ctrl/Alt Hold Down + Mouse Move? That would make the most sense. Then you just press some key to snap back forward.
Are there any plans to have some kind of minor g-force related screen panning when turning or using the afterburner? Basically, if you hit a hard right turn your virtual head moves to the left. If you hit the afterburner, you head snaps back a little so, the screen looks up a tad.