10 ms sounds completely out of reach right now. A quick search shows some black-and-white boards advertising 7.5 FPS (150ms) in 2019.
I was working with a three-color e-ink board from Pimoroni recently and a full screen refresh would take 20+ seconds. Looks very nice when it's done, but definitely unusable for anything real-time.
What are your expectations and applications for color in an e-ink writable tablet? The best available color e-ink displays support a spot color palette of 3-7 colors. They're nowhere near being able to show a full-color image. If you want something for illustration, a Cintiq is the best option and you get to use software (like Illustrator) that's up to the task. Even the Cintiq Pro displays are only able to hit about 15 ms response time.
I'm hoping for a world where e-ink gets iPad levels of repsonsiveness, honestly. I like the displays alot, they render text beautifully at a high DPI (at least ones i've seen).
Its just that they don't have the best response time. Thats really my limiting factor.
I don't expect them to replace the iPad, for instance, but for using as a true digital notebook and book reader (magazines too, if the color e-inks get better) they look and feel ideal for this, except for the lag time in responsiveness, that's the part that kills it for me every time I investigate it.
That would be really compelling to me. Especially if you can get the latency down into the 10 ms range.