Maybe eBay perhaps? I know a lot of recumbent riders often upgrade their cromo forks for bouncy ones and will often sell their old forks. Haven't seen any listed for a while though. You could also try to place a want ad at hostelshoppe.com and bentrideronline.com.

Also, Gaerlan sells the Dahon handle bar stems that will fit 1" head tubes. Maybe it's easier getting one of these stems plus a head tube reducer and a 1" threaded/less cromo fork. Can you adapt your current handlebar setup?