There is a fair amount at 235 - 255 that can be recovered:

On the other hand, there is still some hard clipping at 255 (in the ion cannon blasts, the light to the right of Yoda, and some of the lights in the falcon's cockpit).

The problem with capturing lower is that you are already losing shadow detail (to the right of the Cloud City catwalk, for example). This is why I mentioned that HDR techniques to combine two different captures would be ideal.

Anyway, for the example clip above I used a simple levels(19,1,255,0,235,false) in AviSynth. Better results may be possible with one of the more advanced filters like Ylevels or SmoothAdjust.

You cannot do this in VirtualDub, because VDub filters work in RGB colourspace - and this "superwhite" information gets lost on the conversion to RGB.