I'm a little surprise there isn't an option for this in FileUtils. Something like FileUtils.touch('/location/for/new', :force => true). I'd be in favor of adding that, or an option to FileUtils.mkpath.
I think touch is a good name because everybody already knows it and it's what people will try out spontaneously before even looking in the docs why it doesn't work. Joel Spolsky explains quite well why this is a good thing.
We don't always blindly import broken designs; for instance Ruby do not have creat(2) equivalent method. "Everybody knows it" is (definitely a good property but) not enough.
When it comes to touch, there already is FileUtils.touch so your urgent needs are already satisfied I believe. Here on Pathname let us consider a clearer design.