It is a pity nobody else comments this really interesting kris.
I ask myself, if the more Keris-like looking krisses, lacking "arrow" feature at the Sogokan grooves (here another arhaic kris WITH it:
http://www.vikingsword.com/vb/showth...ght=early+kris), are not more likely coming from North Borneo and/or Brunei. I think of krisses like these:
http://www.oriental-arms.com/item.php?id=1533
http://www.swordsantiqueweapons.com/s778_full.html
To me the hilt with the leaf motif looks also kind of like from there.