Jim,
When I was in Cape Town, where you are, I shopped around a bit for XT600 spares and found some good rear rims and a battery. The second hand rims I got from the guy in Muizenberg, he is on the through road on the other side of the booze shop. He is probably the person to sell you second hand fork legs and / or tell you how to source spare parts.
Will, by the way,
www.kedo.de and /or
www.wunderlich.de not ship to SA? Maybe worth a phonecall to them!
As to spare prices, the originals etc are indeed very expensive, but you can already save a lot by shopping around for seals, O-rings, bearings etc. at specialised hardware stores. You get the same items, without the Yamaha wrapper, for 20% of the price!
Auke