509524 Drag and Drop Webpage Layout

I've multiple page layouts stored in MySQL database, using tables syntax to design the page. I also have a list of available blocks (widgets), and I want the client to be able to assign some (or all) of them to any table's cell of the page layout (see screenshot). Prefeable solution is Ajax drag and drop but I can discuss and any other solution. Of course I need the final design and content to be saved.