I have written an Android application and a small belonging plugin (xml-rpc extension) to track my journeys (GPS trackpoints and waypoints). The application can (reverse) geocode, generate and upload a GPX file and attach it to a new or existing post (the post is created by the plugin). Maybe it is worth to integrate this in the WordPress Android application. The sources (also of the plugin) are available on github: https://github.com/M66B/BackPackTrack. Is there any interest in this?