OpenStreetMap / Offline Maps? - any Corona examples here?

I’d be interested how to implement offline maps with Corona using OpenStreetMaps (i.e. be in control of all aspects).  Can do custom overlays etc as required using Corona display objects etc then…

Question:  Anyone done this?  Any tutorial/open source Corona code for implementing offline maps available somewhere?  

Background: I’m assuming there would be the challenges of (a) how you download required maps at the required resolutions for offline usage for the area you are interested in, and then (b) how to “tile” sections/images of the map, swapping them in/out of memory/rendered as required.   Any better ideas here other than using a map source such as OpenStreetMaps?