Basically it's a replacement Gamecube port cover for the Wii, that has sliding covers instead of popping up.
I really want to get one as a gift for a friend (I don't have a gamecube library myself, And I plan on just getting the good games through the WiiU's virtual console), but these are difficult to find! The only model i can find is "Cyber-lid (for Wii)"
Any help would be appreciated.
Manufacturer's link: http://home.cybergadget.co.jp/products/4544859007392.html
In Japanese, and it's listed as discontinued.