I am creating a Website where users can create text documents and am using ckeditor for that. It also has an "inline-edit" feature which allows users to click on an html element and then bring up the html code in the editor. This seems like a good starting point. What you would also need is code for the users to add pages, images and change/edit the global stylesheet which should be fairly basic using any kind of server sided technology.
I don't quite understand what you mean by 'only saving in the users directory'. I would recommend to never save users files directly on the hard-drive of your server. Use a database for storage instead. You never know how many costumers your website might end up having. By saving on the hard-drive you are very limited in the amount of data your users can upload. In one of my projects I am currently switching from SQL to a Cassandra database cluster which can theoretically hold an unlimited amount of data. If you use the hard-drive for storage you might potentially run out of storage space very fast, especially if your costumers are allowed to upload images and video files to their sites. It is also harder to bill your costumers for the storage space they are using. By storing in a database you can find out how much space a costumer consumes by running a query and then bill them accordingly.
If you also want your costumers to be able to create images inside your website creator I would recomment SVG-Edit. It is a free Web-based SVG editor which can save your users images as SVG or export them as PNGs which your users can then bind into their website.