I could not find a way to index a polygon (rectangle) crossing the 180th meridian.
Common sense suggest to let some longitudes overflow +- 180 like in this example:

{"type"=>"Polygon", "coordinates"=>[[[-185.0, 30], [-165.0, 30], [-165.0, 50], [-185.0, 50], [-185.0, 30]]]}

but it fails with the infamous error "Can't extract geo keys from object, malformed geometry?".

If I normalize the coordinates to not overflow +-180, then I don't see how mongodb could distinguish that small polygon from a large band going from meridian -165 to meridian +175.

I could try to split my polygon into two across the 180 meridian but then I fall onto https://jira.mongodb.org/browse/SERVER-8907