Web-based wysiwyg html layout editor?

Question

I'm not talking about WYSIWYG text editor. FCKEditor, TinyMCE is not an option. The questions is about a web based JS (maybe Flash) html layout editor, that allows creating of DIV's, settings basic parameters of them (width, height, margins, paddings) and allows editing of raw html/css for advanced purposes.

The only one close enough is Construct, but it's very simple and uses keyboard (i need mouse-based interface).

Answer 1

give the tool of those YUI guys a try:
http://developer.yahoo.com/yui/grids/builder/

Answer 2

Here is something that can come in really helpfull: http://jsbin.com/iyuwi

You will need to make some adjustments, in order to dynamically create more divs.