Parang Ilang Mata Bayu part 2

[VVV]

Unfortunately the old thread on Bayu, as well as other rare Dayak weapons like the Dohong, has been closed.

http://www.vikingsword.com/vb/showthread.php?t=3526

But I hope to continue the discussion with these two Bayu I have acquired since then as well as the article of E Banks, The Keris Sulok or Sundang, MBRAS, August 1940.
In the article Banks brings up some change in taste of blades among different dayak tribes, like the Iban who already at that time prefered the Ilang or Duku for the traditional Niabor or Langgai Tinggang. Also he brings up that "...the Kayan and Kenyah tribe nowadays concentrates on the carving of the hilt and the decoration of the sheath rather than on the beautification of the actual sword blades." He then presents his theory that the old and scarce Kenyah Bayu might be derived from the straight Sulu Kris (Keris Sulok Raja Laut). This based on that both are double edged and some resemblance with the fretwork between the Kris and some of the other Dayak parang. He also speculates that the Bayu is the oldest Dayak Parang and that the regular Ilang is derived from this blade. So the evolution would be the straight Kris as inspiration and then the Bayu to the Dayak Parang with false edge to the Ilang.
I am not that convinced on his conclusions, seeing more resemblance with the Dayak spearblades, as well as maybe the Dohong, to the Bayu.
Another influence might be the Barong, or Pida as it's called among the Moro living on Borneo? But I haven't seen any double edged shandigans collected in Borneo.
I look forward to the opinions of the other forumites.

Michael