No attempts, but it has been discussed… multiple times.
Everything exists in theory to make a weight gain system feasible, but nobody has tried to code it all yet.
If you want one, give it a try. Until someone picks it up, it will remain a ‘what if’. If you can use the editor (see my post in link 2) to build an automated weight gain mod (that doesn’t require manual clothes swapping) I think you’ll impress a lot of people here and folk will trip over themselves to contribute and help out.
Once there’s proof of concept, you don’t need to worry about art assets.
