If there's enough interest, we'll definitely be working on this next. It would just require a slight restructuring of our data to make the lookups as efficient as possible.
+1 to reverse geocoding support. Our app runs around 25k/day reverse geocode calls to OSM and Mapquest's Nominatim. We are projecting up to 4x growth within the year so an accurate, bulk and cheap service will help ease our pain. And oh, we're based and operating in the Philippines (which hopefully you can add soon as well).