I know it's not pre-war and not baseball, but I recently picked up the card that is arguably the holy grail of American auto racing cards -- a Fred Lorenzen with car card from the 1972 STP set. This card is now the centerpiece of my collection.
Racing collector extraordinaire Jon Hardgrove has written in the past over on the net54 nons-sports forum that he had seen one example of the card in 26 years. Another long-time collector of the set told me when I talked with her on the phone earlier this year that it took her 20 years to find a Lorenzen with car card -- and that card has a pinhole in it from being pinned to someone's wall back in the day.
I have posted about the "find" in the racing card thread that occasionally sees some interest on this board. The card was included in a box of items that sold for $40 at a live auction of items that were owned by a recently deceased racing photographer. I was not the original buyer at the live auction for $40. But, clearly, no one attending the live auction knew what they were looking at when the box sold for $40. The box included one Lorenzen with car card and several of the nearly as rare Lorenzen portrait card from the same set.
http://net54baseball.com/showthread.php?t=220356&page=6
