I tripped over this brochure in my travels. My eye was drawn to the bit that said that the update voltage was 0.5 micro-amps per cm2, and that it runs off 5V. Maybe this is outside the realm of possibility, but I love the idea that it draws no current when it is not updating. Now this is a 33-segment display, and not a bitmap, but I assume you can have whatever you want if you pay enough.
I’d quite like to futz around with a Dev Kit to see how much power it draws in practice.
DigiKey has one for $70