The US solider cards were also given away as a freebie in Plato magazine issue 91. It's still available on Philibertnet but gets a bit pricey when shipping is added on.
The magazine also includes a rules variant when using the John Reese Europe soldier card as the card is inspired by jazzman James Reese Europe:
One of the players takes the character of John Reese in place of a French soldier. Very frail, John cannot bear more than two Hard Knocks, and the third is fatal to him. Once per game, he can, instead of revealing his Support tile, play a piece of Jazz to his friends. Delighted and exhilarated, the other players can then discard one of their Hard Knock cards! This improvised concert replaces the Support phase, and all players take back the Support tiles they had played.