The filing and its now-removed picture, spotted by WirelessGoodness and then picked up by Digital Foundry, was submitted by Nintendo and wireless module maker Mitsumi.

As Digital Foundry points out, the wider top screen display seen above isn't used by any of the existing Nintendo DS hardware iterations, nor is the CTR branding--the original Nintendo DS is code-named NTR, the Nintendo DSi TWL, and the DSi XL UTL.

Apart from the larger top display, the board packs slots for both Nintendo DS cartridges and SD memory cards--things that are already included in current models and would be required for the promised backwards compatibility of the Nintendo 3DS.

It's unclear if only one or both of the screens would provide the promised three-dimensional visuals without the need for specialized glasses, though the top screen looks to be about the same size as the Nintendo 3DS' rumored 3D Sharp display.

Nintendo plans to properly unveil the Nintendo 3DS and its glasses-free visual effects at this year's Electronic Entertainment Expo (E3), which runs from June 15-17, 2010.