I've quite a bit of Nintendo artwork from their press images. For now though here's some of the more "artsy" stuff (Sorry for the super small thumbnails! Bayimg doesn't supply very big thumbs. XD ):
Disaster: Day of Crisis
1,500 x 2,122
Project H.A.M.M.E.R.
2,564 x 4,000
Elebits
2,160 x 1,458
Fire Emblem: Radiant Dawn
7,584 x 7,584