Some 3DS specs (cards maximun size)

[MrT-Tar]

zarx said:

I expect it to go as high as 16 if not 32 GB by the end of it's life like the DS went from 8-64MB at launch to up to 512MB (A.S.H. the biggest game I know of was only 256MB tho)

I'm not sure, but I think Ninokuni comes on a 512MB DS card.  Its the only game currently to do so