In one of my recent projects, I had to build a tiles background for a resizeable window and an element that the user can move and resize.
For the tiles background I used the excellent CanvasBackground.
For the elements I used Object Handles which reside on Google code.
Here you can find a little sample combining both features. Source code is here.
If you wish to see my implementation - here is a link to a part of the application I'm working on.