Nintendo may have successfully unveiled Wii to the gaming public at E3, but apparently speakers in the remote controller wasn't the only surprise in store, with rumours still persisting that the Big N still has further secrets up their collective sleeves.

CNN's Chris Morris made a suggestion towards what this could be in his latest Game Over column, suggesting that the clue came from the appearance of custom Reggie, Shiggy and Iwatee' characters in the concluding game of Wii Tennis at Nintendo's E3 conference.

Speaking to Morris, Nintendo's Shigeru Miyamoto comments on Sony's decision to ape Nintendo's motion-sensitive technology, "On the flipside, I suppose they must be worried about any other functionality we may announce."

The appearance of custom-characters in Wii Tennis, in which a member of the public became the first person to play a Wii title, initially appeared to be nothing more than a trick to dramatise the action. Further comments from Miyamoto-san during the interview, however, continue to allude towards such a feature appearing in the Wii, "...we have some different ideas about how to take advantage of that functionality - and we will be sharing that type of functionality with third parties."

Unlike similar face grabbing technology via the Sony EyeToy, the characters within Wii Tennis sported a cleaner, caricatured style of the Nintendo heads that they were impersonating, opposed to using a photo simply as a texture. Exactly how this works remains a mystery for the moment, however, we hope to find out further information and have confirmation of the functionality soon.