I've installed OffMaps and its a great system - the only problem is that the NZ maps are incomplete.
Pauanui doesn't exist, Tairua has only a main road, Ngongotaha & Kaukapakapa are missing alot of detail.
So the solution seems to be better caching for the native Maps app. My experience is that it only caches the most recent views and Google searches seem to back that up.
Does anyone know a way to allocate Maps a certain amount of disk space? or any other tricks to manipulate its caching mechanism?