Today I've submitted a customization of the EXT box. You can see the submission on Exts forum or below. A demo can be viewed here: http://00367586.aspnethosting.dk/vista-dark-theme/

Hi all!
I've styled the box (see Ext.Element boxWrap()) to look like the Vista Dark Theme. I'm not a designer and this is the first time I've tried to do this, so the design is not flawless but I'm pretty happy with the results.
For now the design only looks good if the background is #4c535c. Use it if you like!
- Jon

vista-dark-theme-box.zip

Example.zip