Nokia n900. Portable linux box, real keyboard. http://neo900.org/ doesn't seem to have gained much traction. https://www.planetcom.co.uk/ seems to be the closest thing we have now.
That thing was awesome. Maemo, the linux OS on it, wasn't.
Your can purchase it and install it on Sony Xperia X and lots of 3rd party supported devices:
https://jolla.com/sailfishx/ http://verdanditeam.com/device/list/
Here's a picture of various devices (some with a keyboard): https://twitter.com/Mister1Magister/status/10510971372101509...