I've been using an Onyx Boox Poke 2 Color for about a year now, mostly to upload epubs and highlight in 4 colors using Google Play Books, which then sends all the highlights to a Google Doc per book. I'd say that device is "color" like the Gameboy Color was "color." It certainly isn't vivid, but the colors are distinguishable.

I wish I knew how to take that output (a really annoying table format) and process it into an outline, though. That would be a real game-changer for me!