Is the wheel still on your car or if not do you still have it? If not in really bad shape they can be restored. I'm sure there are others that perform the same service, but Rim Blow Buddy is a company that seams to have a quality product. I believe they offer a restoration service, repair parts and restored wheels.
http://www.therimblowbuddy.com/our-store/536/
I have seen the 3 spoke on E-Bay at times with prices up to $2,500.00! These wheels were sourced from the full size Ford and were also installed in Torinos, Mustangs, T-Birds and sister Mercury vehicles. So there were plenty of them out there, but were probably left in the car when the vehicle was scrapped. They are a great looking wheel and really dressed the interior up, but a lot of people hated them because of not being able to get used to the horn switch in the rim! (Try speed shifting a big block car with a 3 spoke and manual steering)!
I know 40+ years later it comes down to supply and demand. But when I see a wheel that was a $39.00 option on the 71's and sold over the counter for $135.00, it makes me cringe a little when I see them approach the 2-3K price range.
Hopefully this info will help you decide how much more you want to torture you credit/debit cards!