Promise
So far we've only seen third-party download game in the Nintendo 3DS eShop, the decent but could-do-better Let's Golf! 3D. That offering is set to multiply significantly by year's end though, as Nintendo announces the 3DS download games on the way before 2012.
Mighty Switch Force from WayForward will see release this Autumn, followed by Mutant Mudds in December. Sandwiched in between is Zen Pinball 3D, down for a wide-open Quarter 4 release date.
Before all that, Europe will receive 3D Classics: Twinbee on 22nd September, with Enjoy Gaming's puzzler Pyramids down for release in September too.