The Twiddler 3 works with Glass, but it takes some hacking.
Here's a brief list of steps:
- Downgrade to XE12
- Disable automatic updates
- Side load the Android Settings app
- Pair the Twiddler
- Side load an app that understands keystrokes
It's pretty involved, so I wrote up a blog post with all the details: http://little418.com/2015/07/google-glass-and-the-twiddler-3.html