Unusual style sheath

[PeterP]

Last weekend I found this empty scabbard at a flea market. It's pretty worn down, quite old, and in bad repair. What attracted me was the unusual style. Could somebody tell me where this style originates? It's not your usual javanese or madurese sheath. I think I've seen it once or twice before, but I can't find another example on the net. It would be nice if somebody could point me to the right direction.
Peter Paul