In www.gonintendo.com there is post telling that there will be a Nintendo event on 22 and 23 of May.
22 to show most of the games and in 23 to show some pre-e3 stuff.
Looks quite believable after what IGN Matt said in his Wii Mailbag and also after the counter in SSBB Page.
Makes perfect sense, in that way Sony doesn´t get an pre-e3 advantage because of their gamers day.