guys one thing to remember is that ILM have prman and thus they can do multisegment motion blur where it blurs the image multiple times within a frame and that's partly how they get that "blown out" white look. I'll take a look at this tomorrow at work and see what i can come up with.
Alan
Ps the particles idea would be so hard to control accurately I think it would drive you into a quivering wreck of a maya artist in the corner
Technical Director - Framestore
Currently working on: Your Highness
IMDB