We do the same in our Visionect Platform - a server component streams images to a WiFi, 3G or ETH enabled E-Ink device. We do sizes from 6" (proper device in casing) to 32" (in color as well).
What's the refresh rate/interactivity/frame rate for your devices? Looks like you guys have lots of awesome options - are there videos of the devices in action or the dev environment?
Are the high prices of devkits primarily driven by the panel cost or for other reasons?
Videos of device in action: https://www.visionect.com/blog/kindle-users-can-your-reader-... (our previous generation device)
High prices are driven due to price of screens and the amount of support we provide. It's a development kit, intended for customers building products. We're not that much of DIY (like a hacked Kindle or the OPs solution), but rather a production ready solution that you can use to prototype and later deploy in field. Examples [1], [2], [3]:
[1]: https://www.visionect.com/blog/joan-honored-for-its-eco-desi... [2]: https://www.visionect.com/blog/smart-shelf-labels-on-electro... [3]: https://www.visionect.com/blog/electronic-paper-at-london-bu...