I made a new extension last night that when someone types [[ it brings up a window right there inline with the editor with search suggestions. It searches farticles and iles, categories, (if you type category:, file: or image:) . And it searches the entire article name, not just the beginning of the name.
You can see a video of it here. http://vimeo.com/15483955
It is written using the MooTools javascript framework. But if anyone would like to port it to use just plain javascript, let me know and we can work together so everyone can use it.
-Adam