I need a bespoke drag and drop web page editor made with jQuery

We need a bespoke web page editor (so we can easily build individual landing pages), built using jQuery with full drag and drop functionality (jQuery ui). It needs to be well optimised, responsive and cross browser compatible.

The editor will effectively load the page elements & information from the database, and will "publish" the result as a HTML file with all the relevant JS includes & CSS.

The page to be edited will appear on the left, with a control panel to the right (with various tabs). The control panel will contain buttons you can drag to the page to add elements (briefly detailed below). The control panel will also contain other aspects including page background colour, and other information which will be loaded from a database (meta keywords, title, etc).

Elements and their attributes need to be saved as "objects", that can be saved in a database for that page (we will handle the database interaction), which can be loaded from the DB when a page is launched in the editor.
Attributes would include x,y and z (bring to front/back) positions, text content for text elements, etc.

Elements include:

Text (With inline text editor support)
Images (With upload and image browsing functionality, and crop/re-size)
Form (Add/remove form fiels (text, textarea, dropdown, checkbox, radio buttons)
Buttons (From image repository, or CSS classes which can be edited (colour, shadow, etc) - these could trigger a form popup or just contain a link.
Video (From youtube link, or using HTML5 Video) - it should be able to choose a video background image and fit the video accordingly, so it looks like its on a screen/tv/laptop screen/etc

There needs to be a snap to grid option (snap to grid on/off, grid visible on/off, etc)

The resulting CSS etc will need to be cross browser compatible (to a degree), this may require different CSS files to be generated on a per browser basis.

If you are interested, please get in touch for the full specification. The set price is a rough placeholder and will be discussed fully with any interested parties.