For gift-giving this recent holiday season I offered to make each of my family a hat of their choosing. My first daughter selected a style I a) had to learn and b) was of a method that took *forever*. It is done. Noro Kureyon varigated yarn (colorway #128, now discontinued) does wonders with this design. It originally started out as the "Diamond Head" pattern in the book, "Hats - a Knitter's dozen". Said daughter asked for the ever-so-popular built-in bill, so with some time spent in trial-and-error, I finally was able to produce her order for her head topper.
How to make the visor? Make the hat 3" longer than needed, fold to make a hem. Cut a bill-shaped piece of plastic and insert at front of hat. Pull the wool a bit to shape it and tack around the bill. Stitches don't show and the bill is integrated into the design.
P.S. Only offer to make this hat for someone you really REALLY love, or you'll be cursing the whole time you are weaving in those thousands of ends.