There has been at least one user working on it, for kivy, so maybe it'll available soon, either as 3rd party package, or as a PR to either project (though it would probably make more sense on kivent).
Yes, you can see examples of games done with kivy in the two contests (kivy.org/#contest), and there are also a few games on the market, it's also interesting to look at kovak's efforts on kivent.org, a 2D game engine built on top of kivy and cymunk, which seems like the way to go for games with a lot of actors.
Did you use ListView, or did you roll your own ScrollView managed content? We are sorry about the state of ListView currently, and plan to redesign it soon, it's really not optimal currently, and not offering a very useful interface either, so maybe you could fix you issues just putting a GridLayout in a ScrollView and fill it as needed (i documented a way to do a publisher/consumer using threads on my blog, it's efficient for these kind of things).
I think startup time has good for very annoying, with android devices of 3 years go, to nearly forgettable, with more modern, high-end devices. I've witnessed nearly instant startups, with devices as the Note 2, not saying it's a solved problem, the cpu speed and even more the read/write speed of the internal storage will have a lot of impact especially on the first start (unpacking python and deps).
For battery usage, i'd love to see data for this, i think drain will come from the amount of action you put in your interface, as well as background processing you'll do, kivy itself, being opengl and cautious about what to update when changes happen, shouldn't add a lot of overhead on this.
I don't think porting to micropython is considered an option, usually, when we want more efficient code, the solution is to do less python, more C, we have a nice integration with Cython, and don't hesitate to go with it as soon as needed.
I confirm there was no money directly spent on promoting kivy. Most of our communication has been directly with the community, through help on irc/google-groups/SO and other places. We did start to improve communication on twitter/g+/facebook, but it's really on our own time, not paying any agency or specialist of these things.
For books, while we were contacted by a few publishers, none of the core-dev authored any, yet. We tried to give a hand, however, reviewing the books when we could, i personnaly reviewed O'Reilly's book, pointing out a few mistakes to the editor, and gave it a good review, as it was, in my opinion, a well written book with very good exemples and explanations. As it seems usual, i got a free book and a little payment for this (that i didn't expect at all when doing it, my motivation was that there was a need for good kivy books).
And i agree we should do more, if not on marketing, at least on communication (there are a few markets that kivy can fully or partially cover already, we don't want to limit these options, just help it grow where users want to use it), but users need to know about it, and to easily get a good understanding of what's possible to do with it. We have a lot of recurring questions about that, as well as people discovering us and asking why they didn't heard about us sooner.
I do think the community could be way bigger, but we need to adapt the tools we use to communicate, irc works very well up to the hundred of connected users we have, probably less at more, and waste a lot of energy in saying the same things over and over again (although the direct interaction with our users is highly appreciable), SO seems to make reuse of explanations much more common, and is sometime more effective than direct documentation.
Anyway, i'm getting away from the point, will cut it there. :)