If there was a 2D equivalent, I'd be interested in tinkering with that, too. And yes, that would probably mean spending 5x ot 10x more than a cheap commercial printer to get a printer than underperformed said cheap commercial printer. But it would be mine, and I would understand it, and be able to mess with it. And fix it if it broke. And use weird inks with it. And so on.
You can probably adapt a printhead from a printer to your 3D printer today if you want a crappy DIY 2D printer and go from there.
My printer today looks nothing like the printer I started with, I’ve switched boards, recompiled my own firmware, the whole bit. I was confident in hacking on it for two reasons:
1) It was open source based
2) Replacement parts are inexpensive
I originally started with a Makerbot 2X which was closed source and $2500 (8+ years ago). Mind you, I didn’t have one at home- we had a couple at work for prototyping.
The slicing software was atrocious, the ability to fix it was hampered by what parts they sold, and the replacement parts were generally very expensive.
My $250 printer was better in every objective measure out of the box than the MakerBot was after years of practice and tuning.
This year my friend’s 2X died and a replacement motherboard was going to be almost as much as the cost of my printer new so he just gave it to me and bought a new printer.
With my newfound confidence from my “cheap” printer, I gutted the 2X and installed an open source motherboard and completely rewired it.
It all started with a printer good enough to be liked by the community and open enough to be modifiable.