I would like to make cornice boards for 4 windows: 2 each in living & dining rooms and I want decorative wood. I would like them to extend 4-5 inches from the wall and be approximately 7" deep. (They are expensive to order & you
only see the catalog pictures from Penney's & Lowe's. Because they are special order, you cannot return). Can I make them from the crown moulding which is readily available?
If you have the ability to make the necessary cuts, you can make them out of just about anything. Crown molding and some 1x flat stock would work. The hard part is going to be the miter cuts on the detail work.
That's just my opinion. But it's free, so take it for what it's worth to you.
Might see if someplace like this has what you are looking for. There are others on line. If you are going to paint it and are not a purist, the extruded foam might work also. Search online. As mentioned, you still need to figure out the miter cuts at some point.