This is a cross I made by using my Copper Black Marans Rooster over my EE Hen shown here:
Her daughters, such as the one shown below:
lay a beautiful Olive colored egg.
When available, I list these eggs on E-Bay under the heading 'Olive-Eggers'. I typically ship the blue eggs that will hatch out the birds that lay the olive eggs. I can also ship olive eggs that will hatch birds that should lay a darker olive egg as well if available.