Custom Project Editor Window

I want to create a custom project editor window to limit the visibility of all the files of the project from the designers. To achieve that I thought of creating a custom project window with the contents of the just the Resources folder.

I'm using EditorGUI.Foldout for creating the tree view but anyone have any idea how each file would be represented in that tree considering that Resources will have Prefabs, Textures and what not. I wanted to have an easy representation like may be a icon for each prefab which can still be dragged in the scene view to create the associating prefab.

Anybody has tried anything similar, please post the challenges/solutions that might be useful.