I created a nice, professional-looking green theme by modifying the gray theme that comes with ext.js 2.0.
To create the theme: I colorized the images using Gimp's colorize function set to hue=159 / saturation=86 / lightness=11. To change the css, I created swatches for the colors in xtheme-gray.css and colorized in Gimp, then replaced the colors in the css. The download includes the swatch sheet for the gray theme.
@DigitalSkyline - thanks for finding the bug. I have redone the css so that all the grays are greens (except the very dark greys, #111, #333, #444 and #555), using the same color shift as I used for the images.
Creating the theme was quite easy to do: an hour or two. I'd be interested in seeing a red theme.
I'm trying to find where to change the BWRAP background-color (see my popup-bg should not be gray)... perhaps you can point me in the right direction?
Also there are a couple more items left to theme, the combobox is not styled, and the grid headers are not styled. I assume the gray theme simply doesn't have those entries which is why we missed them ... here's my first attempt at a red theme, notice the problems I mentioned: