timmmay: Not a bad idea, an extractor. Again it's the hole in the ceiling thing, you might as well have a proper DVS if you do that.
With a skylight it'd need to be double glazed, and covered so as not to let light in. Plus in my house a skylight in the bedroom would just lead into the huge tall ceiling, which until well after sunset would be pretty warm. I had a temperature monitor up there once, it got up to around 40 degrees from memory. It's not well ventilated, which is handy in winter, but not so much in summer.
Our skylights are double glazed with roller blind and remote electric opening with a rain sensor. Just the kind a geek would like ;)