Finally I updated iDempiere Atlantic Theme to 5.1 (also compatible with iDempiere 6.1) after not touching it for a couple of years. Now it’s using the latest zk theme (8.6.1) and converted to archive based theme instead of folder based theme. With this update you can customize it more easily using less as I demonstrated it in this tutorial. It’s also possible now for user to switch theme without affecting other users, I will create the Theme Switcher plugin in the next couple of days.
You can find more information in the plugin page. If you find any issue please post it in the idempiere google groups, I’ll try my best to help.