Michael:
I think the pictures you show above from the two references clearly illustrate the similarity in style between Artzi's example and the well provenanced published examples. These shorter hilted forms do seem to be attributable, at least in part, to the N. Borneo muslim group (albeit perhaps translocated from Mindanao). Since we are talking basically of transplanted Moro people, the style of carving may be quite similar to Mindanao, but the shorter hilt seems distinctive to N. Borneo.
Ian.
And then there is this one that Dan Wilke and I found in Manila. Where is this hilt from?