I had the same problem on my '84 some years back. Finding the shaft at a salvage yard proved futile, no aftermarkets were available, and professional fabrication was very costly. I have little advice for you sorry but I do have a Ranger story.
I DON'T advise anyone doing this as its fairly dangerous, but this will give you an idea of the toughness of these trucks.
The 2.3l motor had near 400k and was rapidly declining, I was also planning on using alot of the parts for a project 85 I had bought. So I decided to run her on the front till she died. Problem was the stubborn ole mule ran another near 20k before I finally burned the tires off it (BF Goodrich A/T - rotated approx every 1-2k). Keep in mind I was just runnin around town, no highway use. light hill climbin around the local fishin holes. Motor was still clickin along!
I just couldn't kill that truck, thats when I became a Ranger man for life. I'm still astonished the stock tranny, transfer case, front shaft and suspension parts could stand up to that kind of punshment. Not to mention over 400k on that little engine that could.