Iceland has recently gone through a two year full dry-run of a four day working week that was hugely successful. It's also being trialled in the UK now. Personally, I would cut the working week to 3 days. And that would include the City.
However, what I want to ask would a four day workimg week work in the USA? Or are people there married to their jobs there rather than their wives - it never seems like that in American sitcoms - it looks like they always have all the time in the world! I mean, see Friends!