Raspberry Pi Clone of the Nintendo Wii, with a slot loading disk drive and SD card reader.
The “Pii” is mostly here because the materials for a prototype are redily available as long as you’re willing to shell out the money. At the core would probably be a Rasberry Pi 3B+, and it could use some modest heat sink and fan to keep it cool. Aside from that is a slot loaded CD drive (mostly for cosmetic effect), and an SD card reader(mostly for similar effect). Though the debug SD card reader I chose has extra USB slots which would be useful for more accessible controller ports.
As for the controller, I would go with the WiiU classic controller. As it has a very basic layout, but a complete set of buttons. And the look really matches the feel the Wii was going for. So in all practicality, this concept really boils down to a white case and the classic controller.
On the software side I think that retro-pi would a sensible skin would be more than enough. Since this build isn’t about being original, it’s about mimicing Nintendo, so having emulators of all of the previous generations on top of native games wouldn’t be a bad idea. And aside from that, it would be any problem to select a Wii theme and an appropriate start up picture for the splash screen.
In terms of appraoch, the cheapest and easiest place to start would be to get the case, and controllers, and then set up and test retro pi. And then from there for the hardware, it seems like it would be worth getting the pieces together, and glueing them down so they work as one disconnected unit. From there I guess I could use card stock or something semi-hard to mark a quick cut out of what it would look like, and then maybe something harder like acrylic.
As for what the final result of a build like this would be. I don’t know, I think something with the Raspberry Pi compute module, with an SD card reader attached to the board, and a spot to mount an internal slim dvd drive connecter, with a few buttons for power and eject would be ideal. A case could probably be 3d printed and then slimmed down to a little slimmer in height, and then try and keep the width and height dimensions.