This is the Crystal Clear theme by Everaldo
I was unable to install original *.jar file in Mozilla 1.6-1.7.xx, neither in SeaMonkey, so I just slightly changed the contents of jar file, so it matches the modern.jar theme, shipped with every Mozilla release. I know, its an ugly way, but I'm not a programmer and thats it.
Replace the modern.jar file, found in chrome directory, with my file, and you'll get Crystal Clear theme under the name "modern". It should work with all recent versions of Mozilla Suite and SeaMonkey