I have talked a little on folding helmets previously. A nice folding helmet is definitely a product that would be of benefit to the urban commuter, and a product that would also reduce some of the barriers to urban cycling for many.
Here is a sweet folding helmet by French studio Agency 360. Named 'Overade', it offers as much protection as a standard helmet but folds up when not in use. Having a closer look at the Agency 360 site it seems they have done work for Look, and a folding bike.