I gotta tell you, when I saw the thumbnail of this on the front page I thought it was a cake! But finding out it was a PIRATE HAT was so much better! Aisy is right, making this out of an ordinary straw hat was pure genius, and on top of that your decoration is pure piratical perfection. It really is display-window gorgeous. Please can we see you in your whole girly pirate outfit?
I can hardly wait for the Elizabethan hat! If you find a suitable felt top hat, you should be able to cut it down to the shape you want. The brim is almost always sewn on separately, which means you can remove it, cut the body down to the right height, and sew the brim back on. You just have to watch that the sides of the hat body are parallel (they are in most styles) or the size will change when you cut it back. The brim can be narrowed simply by removing the edge banding and wire if there is one, trimming the felt to size, and sewing the tape back on. This will usually work for a straight-sided straw hat too, if you find one.
I'm clicking "Arrrr! This rocks!"