Interesting question TW!
This example is very unlikely to be from the Philippines.
The sheath is very similar to the constructions used by the Aka people of Assam/Tibet. The usual sword to occupy this sheath is one they make themselves which has a long (48 inch), single-edged blade with a handle that varies in length, sometimes allowing a two-handed use. These very long swords were called
wetzpa, while shorter ones were called
wetzfa and
dao were called
wetza (Heath, 1999). The shorter swords were often of Tibetan manufacture.
Photographs of a similar example appear on The Dha Index (no. C0047) and can be found here:
http://dharesearch.bowditch.us/C0047.htm. That example is referred to as "a Kachin type
dao?," but that attribution would be incorrect based on the evidence provided by Heath.
I feel fairly confident in identifying this one as Aka in origin, probably with a Tibetan blade. An unusual and interesting piece. I would be interested in buying it if it were for sale.
Ian.
Heath, I.
Armies of the 19th Century: Asia. 3. North-East India. Foundry Books: Guernsey, 1999, p. 29