Hi John- Rusted out windshield frames is a common problems and has been discussed before on the forum try a couple of different searches on windshield, windscreen and you should find some useful information in previous posts. Here is one
http://www.mapleleafup.org/forums/sh...dscreen+frames
If someone has found a source for the stock for Pattern 13 I'm sure a number of people will be interested. I've talked with sheet metal fabricating outfits and have found one who said no problem to do it but $$$$ for the setup once that is done then bending up the stock is not a real problem.
As you will see from the thread above my approach on the Pat 12 was to use NOS M-Series frames.
Good luck and keep us posted on what you find. If you find a place down your way that has the stock it would probably be cheaper then having it made new in North America.
Cheers Phil