My condolences to all fellow bidders...
I'm stumped, too. Some Parang Nabur blades are similar but I can't recall a similarly extensive fuller. I was thinking more of a Ladieng without the usual broadened tip. The light construction seems to suggest a fighting piece rather than a tool and I hoped the obscure hilt would help to pin down the origin of this beast eventually.
I'm not sure about the blade - a decent etching might reveal more about the forging process. However, is it possible to grind this tip shape out of an European blade without getting a very thin tip where the fuller would pass, Ian?
Regards,
Kai