I've got a similar one from the days of Epic. Gav Thorpe made up an example Chapter called the "War Lions" in an article on adapting detachments. They are from a Forge World and

"like to have lots of tanks and their greater access to the Tech-Priests' technology means they can maintain a large number of Dreadnoughts in comparison to other Chapters."

There's no mention of their colour scheme or what-not.