Any competant armourer should be able to make this for you.
Stainless steel would be the way to go for the attributes you want, 18Ga stainless would be quite rigid.
Cost... likely around $400-600.00 for something that looks like it is supposed to fit a human.
Check this guy... he can do it... I have seen some of his work he has done stuff like this..
www.thak.ca