Typically windows like this are metal clad - found from commercial manufacturers as opposed to residential.

This is a commercial type window. The one here is from Western Windows

walls+windows - flawless design decision

This is breathtaking! I wonder though about the stair rails. Would it be safe in a home with children? It seems that it would be far too easy for a child to climb on the horizontal rails and fall G-d forbid.

Look for a fiberglass window company. They are able to do the colour throughout. I went with Accurate Dorwin for my house. They are out of Winnipeg Canada