Try to buy a set of 15-inch 1960's peaked-spoke American TT's, say 15x7. 14-inchers are somewhat plentiful but 15's are, as SK said, "paydirt."
I agree, Day 2 might not become a national fad but it has already become a 'niche' fad among specialized guys like those of us here on Y-net. Try buying a still-in-box SW tach from the '60s. Cha-ching! Even the old $25 Sun Super II tachs are now fetching the bucks. How about Dana/Nickey/etc. welded-together traction bars a-la '67 Camaro? Ka-ching-ching! (Someone should re-pop these.)
Once something becomes "cool" the prices almost always reflect it. That's just plain Business 101.
Oh, and while many of the guys here at Y-net complain about "ePay," many of those same people watch eBay like hawks, looking for those old Day 2 'ka-ching' items, or anything else for that matter.
For the record, I watch eBay for all kinds of stuff. I love eBay. Made money there too!