I'm thinking that though this '41 pickup is similar/identical to at least the '39/'40, that much of the cab roof though smaller is very close in shape as the '48-'52. A back woods/off the beaten track junk yard may still have something like that. Even a Chevy pickup might have that general shape. What ever you do, expect to spend some time fabbing and beating in sheet metal. Then you might even find a complete better cab at that back woods junky.