The last time I read the Quran (which addmittedly was a while ago) the only reference to covering up was addressed to the prophet's wives. As I remember it they were told to cover their breast. But of course there are always problems when you translate any text. My Arabic isn't good enough to read it in the original.
It always struck me as absurd to make women cover themselves to avoid men's lustful gaze, is getting it completly the wrong way round. The subtext here is that men can't control themselves, and are being let off the hook. It reminds me of Golda Meir's comment when it was mooted that there should be a curfew for women as so many were being attacked and raped. She asked 'Why the women?' given that it is the men that are committing the crimes, surely it should be the men whose movements should be restricted.
Religious issues aside (and I'm sure by now you all know my opinions on that!) it is the resstriction and controlling of women that is offensive. I'm not sure that the act of wearing a headscarf, if it really is the woman's own choice, not something that she has been coerced into by overt or subtle means, is really a problem.