From what I understood from some posts in the old lighthouse forum, it seems that Fall Blau will never reach the market. Apparently Graviteam sold the rights to a publisher, so even if they have the data and everything, they can't release it. And the publisher never released the add-on, it seems that it wasn't even released in Russia (?).
But Russian modders are doing a good job in creating missions and new units, I can't say I have had time to play everyone of them yet
Graviteam released their Kharkov 1943 wargame in Russia in September, and a while ago they talked about another tank sim, so who knows, the future of Steel Fury might be in development. I hope they'll find a decent publisher