What I really need, though, would be an ultrawide aspect colour e-ink display. Something with vibrant colours though, not the pastel-like weak shades I've seen so far.

The new e-ink colour panels seem fantastic, I'd need a colour version of their e-paper price labels.

edit: something like this https://www.visionect.com/blog/color-epaper-wins-gold/ but in the smaller shelf label form, ultrawide aspect ratio under 10 inches.

Is there a part number for this LCD? It looks perfect for a project I have.

The only one I can find with a resolution of 400x96 is the Sharp LQ042B5DG01 / LQ042B5DG02, a 4.2" TFT LCD with an aspect ratio of 5:2, outline dimensions of 123.0x35.3x7.5mm and a 6-bit digital RGB interface.

That is indeed the right display. You should know that this display is pretty old - the viewing angle is bad, it needs power to a very big (for the display) CCFL, and documentation isn't the greatest (though a couple hours should be enough to sort it out). I did this project a while back, otherwise I'd be writing a lot more down. It's a fun project - it seems to be a right of passage for a lot of Japanese hobbyists that live around Akihabara.

Very wide aspect ratio LCDs are a bit hard to find in such small sizes, do you know a similar display that are LEDs instead of CCFL?

These are known as a bar-type LCD (at least in China). Things like this: https://www.alibaba.com/product-detail/bar-type-lcd-3-9-inches_60371235287.html?spm=a2700.7724838.2017115.10.60dc3cd9pcQ7HL

Ah, "bar type LCD", thank you! That will help me in my search!

also try ultrawide aspect

thanks for bringing this up again - I found a cool one I'm going to try. https://www.soselectronic.com/products/winstar/wf52qtlbsdbn0-cob-bar-tft-wf52qtlbsdbn0-229078

I think I made a mistake - this is an lta042b010f

http://naruken.cweb.tk/labo/lta042b010f/