This has been an interesting discussion so far. After a little more research: I will definitely need Android 4.1 at a minimum, with upgrades to later releases, for accessibility reasons, and preferably "plain" Android, i.e., without a phone manufacturer's user interface modifications. This way, the accessibility support (speech, braille etc.) will be more reliable, as the user interface is that supplied by Google, whose developers are responsible for the accessibility. (So far as I know, the major phone manufacturers do not have expertise in this area in relation to Android.) Unrestricted access to the device for replacing operating system images is highly desirable. The Nexus phones appear to be the closest current option, but some of the newer phones from various manufacturers have better hardware specifications. It might be best to wait and observe whether a new Nexus model is release during my purchasing time-frame. Alterantively, the Galaxy S III looks attractive among current models, though it apparently lacks LTE support.