Unusual Sumatran sword, maybe Mandailing?

[VVV]

This tricky sword maybe some of you recognise from the Baltimore show?
I got it from Artzi and promised to share whatever I could find out about it on the forum.
My first impression was that it probably was from the Moluccas.
The blade looks a bit like Tanimbar and the hilt like those sometimes seen on swords from Buru and Obi.
But the quality is much better as well as the motifs didn't match that region.
I discussed it with Arjan who gave me the idea that it maybe could be Sumatran.
After some more research I think it probably is Mandailing.
That based on some related features on the few Mandailing blades I found in the Leiden archives (f.i. 769-23), as well as the motifs on this sword.
The Mandailing tribe are probably ex-Batak, but became Muslim quite early.
Here is a nice site about this people and some old pictures http://www.mandailing.org/Eng/indexeng.html

Michael