[zydeco]

I did something similar as an easter egg, but with classic black and white Mac UI, but I never thought to publish it as a library.

[bangonkeyboard]

Classic Note [0][1] ran with the classic Mac aesthetic and was very well done, but is unfortunately no longer in the App Store.

[0]: http://www.digitalworlds-ent.com/classicnote/

[1]: https://appadvice.com/app/classic-note/628565312

[ygra]

I've recently devoted half a weekend to implementing the Windows 3.1 style as WPF styles. There's something about taking a modern UI toolkit and making it look like the old days :)