When an oil company wanted to create value-added services to it's loyal customers especially for fuel card users they found us with interesting requirements

a route planner website which adds POIs (their fuel stations) as waypoints to the planned route
mobile apps for Android and iOS with offline (!) mode to search nearby places (fuel stations) and to show routes (with waypoints) planned on the web
7 languages and even more countries
and much more (the devil is in the details): truck navigation, toll calculations, fuel consumption calculations, offline mapping with the mobile apps
We have good experience with Drupal, Openlayers, OpenStreetMap, Google Maps API.
For creating HTML5 based mobile apps we already used Phonegap so we accepted the challenge.
This is an ongoing project and at the time of DrupalCon Prague the website will be up and running so in the first part of the session I will demonstrate our solutions live.

I will share our real-world experiences powering an offline mapping mobile app with Drupal too:

download (refresh) POI database for offline usage (services)
download map of for your planned route (mapbox, mbtiles, leaflet)