You are right Ben. In my opienion, RadTabStrip is good approach to get the similar appearance and functionality. Checkout the demo which shows how to set VerticalLeft Orientation to get same appearance.
TabStrip / Orientation
Now, you can handle the client side events to show corresponding pageviews on mousehovering the tabs. These links will be of help in this.
In order to show modal window, use the RadWindow control. Checkout the demo.
Returning Values from a Dialog
(Check the second window, which is modal, by setting the Modal property to True).
Have a nice day. :)