I did a Cloud costume for CNA last summer (my first time cosplaying ^_^) and someone gave me a really great idea for the shoulder armor. I feel bad though cause I can't remember who suggested this idea to my before, but if they are reading this, then credit goes to you!
Anyway, the idea is to get a basketball, cut it in half, or quarter or whatever shape you need, turn it inside out and paint it. I have to warn you though that when I first did it, the paint came off very easily cause it was over rubber, so either use a primer first, or use some glaze stuff after you paint it. Then I attached it to the suspenders I made using small screws. I also had small wine bottle corks for the spokes, but they fell off after the first day -_-