Dynamic Menu Created from Sharepoint Content

I have been tasked with creating a custom menu that is generated based on site content. This would be similar to the out-of-the-box menus with which Sharepoint is shipped. However, the following requirements apply:

• The menu will only be 3 levels deep
• Top level links will link to the top level sites of the SPCollections
• Link order can be specified by site owners
• Hover the top level link will display a flyout
• The fly out will be divided into two columns
• Column 1 will include the top ten recently updated pages of the top level site of the hovered site collection
  
• Column 2 will include links to all other sites in the hovered site collection
• Hovering over site links will display another flyout that will include links to the site (to be defined).
• The menu will be driven from actual sharepoint content, not statically created

So this should be fun. In my view this includes a few major tasks

1. Generate a menu statically. In other words, how to make the flyouts flyout, the styling of the thang, etc.
   
2. Get the information (traverse SPSites, SPWebs, and content??, leverage one of the menu datasources, or one of the menus themselves?)
3. Generate the menu from code based on the data. (create an data bindable user control?, generate by looping?)
   
4. Deploy to the portal (user control/web part?, package as a feature or on the master page?)

I need to do a little more research to see if anyone has done this and there are one or more things out there I can use as a starting point or just start from scratch. However, thus far I have come up with a couple things I could use. First of all the telerik rad menu control looks promising for a starting point for the GUI. It looks like one could create such a menu using the control.

Secondly, I was checking out the navigation settings and noted that the site collection navigation can be administered through the site settings, including what links to show, custom titles, and most importantly, defining the order. That data has to be persisted somewhere, so it can likely be used as a basis for the menu data.