Well, we don't get them, but Europe does!
http://www.nintendolife.com/news/2012/08/kingdom_hearts_3d_ar_cards_drop_into_club_nintendo_ukTheir club nintendo gets a pack of 3 new cards (not randomized, so only 3 new cards total.)
If this ends up being anything like the Kid Icarus cards, they'll be stupid hard to get in NA but available in EU and JP.
xp Hopefully at least you can just scan images posted online and have that work? I know the scans from Japanese and European cards (which did look a bit different) still worked on Kid Icarus.
But then again, KH seems to have FAR fewer cards than KI, so maybe there will be hope for us later.