I'm a little surprised at the difficulty locating bikes like the Schwinn American or just Schwinn "cruiser-style" balloon tire bikes in general, especially from the era cited. I wonder if this is an issue of location, because I see this sort of thing pop up with frequency on our local CL, at local auctions, at flea markets, and at garage/yard sales. What I don't see much of are frames of this ilk in larger sizes. Seems like the small and medium frame sizes are out there in abundance, but the big ones are few and far between. I'm also a little taken aback with regard to the pricing the OP is seeing...I've not experienced anything close to the one grand bar, even at swaps. The OP sounds like he or she is searching up and down the East Coast, so my suggestion would be to expand the search out here to the wilds of the Midwest. Good luck!