Some of us have this love/hate relationship with test scores. Yes, they're not going away, and we know many things are based on scores, not the least of which is funding.
But the kind of skills that students gain from 1-to-1, such as how to maximize their own learning styles, how to evaluate information, how to become autonomous self-directed learners, how to create content and publish to the world ... does not necessarily show up on standardized test scores.
The latest eSchool News, however, hints at some positive results coming soon. While not specifically about 1-to-1, the report coming out soon is wide and deep - 9 states, and talks about "student achievement" as opposed to test scores, exactly. Here's the link.