You can but you will have to edit a lot of templates. It would be best to use Expression Blend to edit the menu items. We have developed the menu in Silverlight to use ContainerBindings and HierarchicalDataTemplate so it support MVVM. You can see that here: http://demos.telerik.com/silverlight/#Menu/DataBinding
As for the layout you will have to use some sort of custom panel. For example the RadUniformGrid may be usefull here.
As for the sub menus you will have to put a lot of effort styling the RadMenuItems. We think to create similar example in our QSF but it is not ready yet and I do not know when it will be released. Creating a menu like the one on our homepage will need very skilled front-end-developer to edit all the templates of the menu so if you are not well familiar with XAML it would be quite difficult.
If you need further assistance we would be glad to help but you will have to do a lot of work.
All the best,
the Telerik team
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