This exists. There’s at least one Amethyst fork called Garnet that allows Monero zaps. 

https://github.com/retrnull/garnet

🤷‍♂️ The beauty of free and open sharing of code and ideas is that people will work towards whatever is best for them 🙂 

 (I haven’t used it and don’t have a dog in whatever debate is happening, but did hear about it so thought I’d share just FYI) 

 There is this web client as well. Both are very new though use cautiously.

https://anarkio.codeberg.page/nostril/#/home/