I had intended my next map to be more substantial, but then when I was questing with a new alt I discovered this little instance which was missing a map so thought I'd knock one out.
It's an instance in Frostfang Sea, and only used in two low level quests as far as I'm aware ('Off to the Ossuary' and 'Severing the Head'), although rather strangely the map style name is 'halas_epic01_necro' - not having played a necro, and certainly never having done the epic, I've no idea if the same map is also used in that quest.
I believe the instance is only available when you're on either 'Off to the Ossuary' or 'Severing the Head'; I have a character on 'Off to the Ossuary' so once the map is in game I'll check that it works for both that quest and also the following one, 'Severing the Head'.
Code:
<ImageStyle Name="halas_epic01_necro" displayname="Cave of Illboding Dark" menugroup="Erollis (Island)" zonerect="-773.4, 117.5, -733, 165">
<ImageFrame Source="images/maps/map_halas_epic01_necro.dds" SourceRect="0,0,436,506" />
</ImageStyle>