Since the 19 has the three windows in front, I would think that you could replace the center one with the opening version that is available on the 22. The windows are made by Diamond Sea Glaze in Canada and the factory could probably get you one if they don't already have one. Replacement should be a "simple" matter of removing the square headed screws, taking the frame out and replacing the whole shebang with the new window.
I'd call the factory and ask for Scott (360) 393-3283. He's a helpful guy and will tell you right away if you can do it. You could e-mail too but with this weather, time is of the essence. :roll:
It's hot here in Virginia too...
On edit: Just looked closely on the website about the 19 and they clearly say:''Diamond Sea Glaze windows with aluminum frames that are powder coated to match the color of the boat. Sliding side windows with screens and standard center opening window.
While it was obviously not "standard" at the time your boat was built, it is now and I bet it's a direct replacement to put one in...no cutting. Let us know how it works out.
Charlie