I always wondered, and still wonder to this day, where does Juggernaut's grey outfit from X-Men Legends II: Rise Of Apocalypse come from?
(http://xboxmedia.gamespy.com/xbox/image/article/653/653507/x-men-legends-ii-rise-of-apocalypse-20050923032902220.jpg)
The closest I could get to its origin is the outfit he wore when he joined the X-Men, which is almost the same as the grey one but with some yellow parts:
(https://uncannyxmen.net/sites/default/files/images/characters/juggernaut/juggernaut-bigcostume2.jpg)
So, has Juggs' full grey outfit ever showed up in the comics (if so, which one?), or is it exclusive to X-Men Legends II: Rise Of Apocalypse?
To my knowledge juggy has really only had 5 outfits including the one you showed.
Red - (https://upload.wikimedia.org/wikipedia/en/thumb/4/44/Juggernaut2.PNG/250px-Juggernaut2.PNG)
Brown - (https://vignette.wikia.nocookie.net/marveldatabase/images/5/5c/Cain_Marko_%28Earth-616%29_from_Dark_Avengers_Vol_1_182.JPG/revision/latest/scale-to-width-down/180?cb=20121018022038)
Kuurth - (https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRwXVUO5I2Da65dW2WXk6o_JsS4ooJK5edouM2aQ0R0rHM9Nv2m)
and Powerless - (https://uncannyxmen.net/sites/default/files/images/characters/juggernaut/juggernaut44.jpg)
I don't think he's ever worn the all-gray outfit in the comics. They probably made it to fit better with the Ultimate skins of the other characters, seeing as how Juggernaut's actual Ultimate skin is rather frightening and would be significantly different from the outfit he wears in X-Men Legends.
That being said, I do really like the all gray outfit.