Thank you for these great themes. I've used them in my Roundcube 0.3.1 for half a year now, and after an upgrade to 0.4-stable today I see the new versions work fine, too.
However, there are a few minor suggestions for improvement.
1) The install process and README file is weird. What's up with the images like background and logo in the root folder that aren't used in the theme at all?
2) Couldn't you switch to one global "include" folder? Changing the five themes needs a lot of repetitive work that could be avoided by slightly changing the folder structure.
3) I very much like the small descriptions for the buttons. But they should always be below the buttons rather than on top of them, and it would be perfect if they could change accordingly to the language chosen. Or at least, maybe you could include a small text file in the skins root folder like "button_text" such that it's easier to change the text.
4) The search box popup-menu is on the right side, beneath the small delete, button, therefore I can't access it. Screenshot:
Imageshack - searcht.pngThat's all I remember right now. Would be great if you could take a look at these things. Thanks for the great work and keep it up!