It's not exactly a text editor, but the web version does allow for markdown. I could not get the integration to work seamlessly with the way that I have my Evernote configured, but you may be able to come up with something if you fiddle with it enough.
Markdown Style Shortcuts
in Productivity
Posted
I love this and I wish there was more markdown integration.
Thank you for the list of markdown that currently works with Evernote!
Check this out:
https://marxi.co/
It's not exactly a text editor, but the web version does allow for markdown. I could not get the integration to work seamlessly with the way that I have my Evernote configured, but you may be able to come up with something if you fiddle with it enough.