The Twin Famicom from Sharp was released around 1986 in Japan as a product licensed by Nintendo. It was basically a combination Famicom and Disk System in one pink-colored, 70's looking unit (Sharp also released a black version of the system, for those looking for something more manly).
If you haven't heard of the Famicom Disk System, it was released by Nintendo in 1985 as an add-on to the Famicom that allowed you to play games recorded on non-standard 3" disks. Disks were a pretty cool idea at the time; you could save your games on the disk instead of a battery, disk games were a lot cheaper since the media was cheaper, and - here's the neat part - there were kiosks in electronic shops in Japan where you could insert a blank Disk System Disk and buy a game to put on the disk. The Disk System was suddenly killed in 1988 when Nintendo literally took them off the shelves due to rampant illegal copying of the disks, but the system lasted long enough to give some great games.. in fact, many of the first really popular NES games (Zelda, Metroid, etc) originally appeared in Disk System format only. In fact, Zelda wasn't released as a cart for the Famicom until 1994!
The Twin Famicom has both a cart port on the top (60 pins) and a disk slot on the front of the console, plus a little switch to go between disk and cart mode. When you turn on the system in disk mode, you get this screen while the console waits for you to insert a disk. The Disk System was a single-sided disk drive, by the way, meaning that you had to flip over the disk when the game asked you to (which actually isn't that often - access time is pretty quick).
Here's a picture of the insides of the Twin Famicom.. it's a pretty tight fit in there, and the system itself is heavier than most consoles. Like the Famicom, this system came with two hard-wired controllers, but it also came with a white and grey light gun complete with a little, retractable, too-small-to-be-useable gunsight.
thanx: A.R.B., mizuyan, mike etler