As you can tell by my previous hacks, I already made a "paper" mario. he's completely flat unless thrown. Also, by the looks of it, my hack's getting a psa of sorts to play like paper mario. So I have no plans to further anything of that theme.
To answer the question of possibility, you could only make a shape of mario, as in a silhouette. Even at that point, any editing to his arms or legs (for proportion) would lead to rigging problems. so you couldn't even get a close shape. lastly, textures only work with his emerald textures, which aren't so U.V. mapped. Take a look at any G&W "textures", they always reflect based on the camera angle and a single texture reflects all around the body. so any texturing wouldn't be close at all.
One breakthrough though, it appears that g&w's data flattens his dimensions on the particular axis by a certain amount, like .0001 or something. By increasing his width through vertexing, I surmise it would be possible to make a "one-slot"(not really
) 3D game and watch. One problem though, his body parts rotate, which would make it look very weird in some animations (without bones disabled).
Lastly, I see no reason making the reverse of my flat mario hack wouldn't make game and watch 3D. Sure he's hard-coded flat, but that could likely be offset with width. Making a complete animation hack like I did would take a long time though, and I'm certainly not doing that anytime soon.