Alongside the Google Maps Wikipedia layer and our iOS nearby articles feature (correct?), the Android/iOS app Geoloqi now has a Wikipedia layer.
Geoloqi is pretty cool. It has some cool geo features you can tack on to your apps too: https://developers.geoloqi.com/
in addition to its own feature set. (If anybody wants a contact, I know the founders.)
Community Organizer at Wikimedia Foundation