"Laptops arrive, and generators-for-hire appear, or suddenly, as in Rwanda, the school is electrified." -- I don't know about Rwanda, but I have spent time in Perú, and laptops in schools without power don't magically get charged by libertarian fairy godparents with portable generators; they just *don't get used.* The Peruvian government had to step up by buying solar panels, though last I heard, these were still not actually distributed.
"In Peru and Paraguay, local, independent software developers and repair shops start popping up." -- Huh? Where in Paraguay are these? I've spent five months there studying their OLPC deployment, and the only repair shop I know of is run by Paraguay Educa, which also deployed the laptops. And the software has been developed by them or through their outreach, as well. Don't ignore the hard work that deployments are putting in to create this capacity. It doesn't just spring fully-formed from the forehead of a community.
"Imagine I take a five-year-old from the most rural part of India and drop her in Paris for a year. She will speak French by the end of that year. Did Paris magnify her knowledge of French? No. It created it from her potential to learn language." -- No. It WOULD be created from the concerted kindness of French people in teaching her, as WELL as her ability to learn (definitely helped by her age). But if nobody talked to her for a year, or if she stayed in a community that spoke only her language within Paris, there is NO guarantee that she would learn French.
"... all of us who can afford a laptop buy one for our kids." -- My research on middle-class parents in Silicon Valley, including many who themselves work in the tech industry, indicates otherwise (forthcoming in CSCW 2011; advance copy available at http://research.morganya.org/ames-cscw11-class.pdf). Many middle-class parents have been massively restricting their children's access to technology -- including computers -- to the very ages that OLPC is targeting. (It's working-class parents who give their children more freedom with technology.)
On the topic of independent evaluations, there are a number out there and many more in progress. Plan Ceibal in Uruguay has been publishing eyes-open (though mostly descriptive) evaluations of their countrywide project. BID will be publishing a (not that favorable) evaluation of the project in Perú soon. I will be writing up my dissertation and publishing it in the next year or so. I recently co-wrote an article with Mark Warschauer that has been published in the current issue of Journal of International Affairs. And there are many evaluations of pilot projects. We're working on it ...