I've been messing around with an e-ink Spectra 6 full colour display. Colours are so much better than Gallery, but the contrast isn't as good. Still makes for better looking photos. I'm merging support in my DIY smart picture frame project this weekend (https://github.com/DDoS/Cadre).
I'm trying to get my hands on a larger display, but man does the e-ink public documentation suck. Still looking for some actual complete documentation and sample driver schematics for the 13" and larger models.