Thanks for sharing the price. The build looks really good, but $400 is a bit steep for anybody on a budget. I think a good quality (high coverage and pixel density) LCD with auto-brightness would be economically competitive, though of course not really the same.
Look into memory reflective lcd's, doesn't look quite like e-ink (and for quite a few of them you have to resort to dithering instead of proper greyscale), but they're considerably cheaper and offer the same power benefits.
Additional benefit is that they're quick to refresh, if you have an application that requires it. I have a calculator built with it, works perfectly.
