These two have the corresponding metacity theme included, based on elegant brit metacity theme (thanks once more to fmrbpensador).
The emerald theme that comes with the MacMenu version of Elegant Cold Blue can be used with the flat version gtk theme (same colors). I haven’t made a mod of the elegant brit emerald to use with the black bar version but the elegant brit emerald should fit though the close button is orange.
They are not global or mac menu ready (see my previous post if you need a global or mac menu version).
Screenshots tell more than words, click them for a larger view.
Install by extracting in your ~/.themes directory or drag and drop the tarball in the theme manager.
Note: to have metacity buttons on the left, open gconf-editor, find the key /apps/metacity/general/button_layout and change it to : menu:minimize,maximize,close
Credits to original authors in the source files.