I picked up a set of complete 5-spd synchros (cones, rings, hubs, sleeves) years ago (way before CRS made them available). At the time, there were only 10 of these sets in existence. Jack T (xwing) arranged a deal with Getrag in Germany for 10 sets. I bought my set for $600 from someone in on the original purchase. Fairly detailed pics of these 5-spd parts can be seen on my web page below. It looks to me that metallurgy and machining won't be so simple.
http://www.stealth316.com/2-awd4.htm