Maybe is a silly thing, but wouldn´t be helpfull a sticky post with pics and serial numbers of the stolen retrobikes? This bikes are harder to sell than modern bikes, and here lots of people follow ebay auctions, sure if one is on the bay someone will discover it...
really sorry to hear about your loss, its totally gutting, i had 4 stolen last december and it still gets to me even a year on, I really hope you get yours back and I'm sure everyone here will keep their eyes open for you!