The 9 Inch Heavy Duty openers are available from Blaine at $13.00 each:
http://www.blainewindow.com
The model is 020, color is 037 - get the teardrop shape and pick what
side you want the crank angled.
You can also get the smaller 6" & 7" ones, but they are not available in
the exact color & shape, and are real expensive. Most people use the
generic replacements available from online or local RV Parts stores.
What is you're still lacking is an adapter plate to change to the larger
hole pattern required. RV places used to carry them, but I've not seen
them in years. The smaller generic openers will fail on the big front &
back windows.
Galvanized screen material you can get from
http://www.cornerhardware.com. Hehr Closing Hooks are still available
from http://all-rite.com, although they are painted red and need to be
stripped.
If you have to replace a missing window, the only real options are
having a local sheetmetal shop fabricate one using another as an
example, or replace the entire assembly with a custom sized Jalousie
type window. Don't have the URL in my head, but I may have it at home
if interested.
Best of luck
RJ