Keep an eye on ebay, they show up with some frequency in various states: from mint to crushed. Make sure you use all plausible search functions, not just 'eldon dragster' but 'eliminator' etc. Also search "slot car junk parts" and "vintage slot car parts" and closely examine the pics. I assembled a Cox mag frame 2E by scouring parts for sale on ebay.
I once bought a mint Eldon Eliminator set at a yard sale for $15, wound up trading it for a set of 1:1 scale Lotus Europa door hinges.
I know you don't want repops, but if you ever choose to go that route, there are some out there.