show me some CMS's that do just this and we'll stop making a new one haha.
How about a CMSCMS ? :-) I suspect that the choice of a CMS has enough personal flavor to it that there will always be a wide variety of them. They are the 'text editors' of the web site management world. When is the last time you though "We've got enough text editors, nobody is going to do another one." ?
I'm pretty sure we already have this. This looks like its already been done by Squarespace.
yes but you have to pay for it and for what it offers, it's a rip off, at least from a web developer's perspective.