Kindle version from amazon. Also notice

At the publisher's request, this title is being sold without Digital Rights Management software (DRM) applied.

You can shop around then and buy it anywhere so long as it's DRM-free, load it into Calibre and convert to a kindle format.

http://www.amazon.com/Peace-Gene-Wolfe-ebook/dp/B008S0E5ZA/

It's on kindle.