Thanks for the help, Norma! I actually already own the K.K. Slider Doubutsu No Mori card. Unfortunately, they don't scan in to the North American GameCube game, even if you use a Japanese e-Reader unit (which I have tried.)
Even if they did scan... the completionist in me would still want the North American card! I don't believe that the Japanese cards have letter code passwords on them, either. I can't entirely tell myself, since I cannot read Japanese, but I thought I heard that before.
And finally, I have meticulously been filling in a spreadsheet of what items are received from both scanning the card and sending the letter code for all 275 villager cards among the four series. I know this was done for Series 1 a long time ago... and the data is likely already out there for the others... but I am enjoying the process of doing that on my own. Call me crazy!
But please, by all means, if you find that card on eBay let me know! I have been checking pretty often during the past month. I actually missed out once already... there was a whole e-Reader package that someone had which included the card, and I got distracted with real life before bidding was over.