Several years, maybe even 5-6 years ago now, I ordered wheaten eggs from Fitz Farms. The eggs were not 8s on the true Marans French scale. They were nice colored eggs, but were more like 4s and 5s on the color scale. So many people say they have 8s and 9s in the Wheatens, but I don't think they are actually going by true color chart, and Fitz Farms actually shows their eggs against the non-french chart where it is pretty easy to get a 7 or 8. Most RIRs would qualify for Marans color on that scale.
Take a look at the real color chart:
http://www.maranschickenclubusa.com/Eggshowinfo.html The photos could be better, but 9s are the color of dark, dark chocolate. A "4" is the color of a dark terracotta pot. Even the eggs at the shows are mostly 5s and 6s of any variety. Occasionally you will see 7s, but not real often.
The chart many use that make it easier to say the color is dark:
http://fitzfarmandpoultry.net/marans-eggs.html
On top of that, I paid $120 for two dozen eggs that arrived a little dirty and out of 28 eggs, 2 hatched. Both roosters. It was the single worst hatch I have ever gotten from shipped eggs and they offered to do nothing about it. I have hatched thousands of chickens. I don't think it was me. When I gently asked about it, they were quite rude. I realize Fitz Farm doesn't control any of the post office actions, but I would be cautious about expectations. They are in it for $$. I have had many dozens of eggs sent directly from founding Marans breeders with a lot better success.
Edited to add better link to the color chart (the really dark one above the #6 is what the "9" should look like):
http://www.enloequarterhorses.com/enloeqh/images/GAdImages/10.jpg