I've managed to extract the themes directory from my Nokia 770 - it's just a bunch of images and some XML files but knowing the structure should help us create some new themes.

I'm making the files available on my website - browse to www.martindolphin.co.uk/770 to download a ZIP file of the themes directory.

If anyone comes up with a nice new theme, we can attempt to write the data back to the device as an additional theme.