Hey Ron-
I'm restoring a pair of early 60's Nissan Patrols right now, and through that effort I chat occasionally with guys from the DesertDatsuns club. Check the For Sale section of their web forum: desertdatsuns.com
There was an orange 240 listed on bringatrailer about 6 months ago that was in decent driver condition. It went for about 14 grand, if memory serves...
EDIT: HAH! - Look what's on Bringatrailer
TODAY...
http://bringatrailer.com/listing/1973-datsun-240z-18/
Finding one without rust will indeed be your biggest challenge- Nissan only used a single layer of etching laquer primer over untreated mild steel sheetmetal back in those days...