Offline Tile Caching support is now available in the Mapbox Android SDK as of version 0.5.1. It was released on 20-December-2014. Here's a basic example of how to get started:
OfflineMapDownloader offlineMapDownloader = OfflineMapDownloader.getOfflineMapDownloader(getActivity());
BoundingBox boundingBox = mapView.getBoundingBox();
CoordinateSpan span = new CoordinateSpan(boundingBox.getLatitudeSpan(), boundingBox.getLongitudeSpan());
CoordinateRegion coordinateRegion = new CoordinateRegion(mapView.getCenter(), span);
offlineMapDownloader.beginDownloadingMapID("MapboxMapID", coordinateRegion, (int) mapView.getZoomLevel(), (int) mapView.getZoomLevel());
To load a previously saved map:
ArrayList<OfflineMapDatabase> offlineMapDatabases = offlineMapDownloader.getMutableOfflineMapDatabases();
OfflineMapDatabase db = offlineMapDatabases.get(0);
OfflineMapTileProvider tp = new OfflineMapTileProvider(getActivity(), db);
offlineMapOverlay = new TilesOverlay(tp);
mapView.addOverlay(offlineMapOverlay);