I, too, like this little knife. The form surely does remind one of a tanto in shirasaya, though the construction details are different. Of course, these are clearly simple working mountings rather than 'resting' storage mounts. The back appears to have a ridge. Is there any trace of a hamon (differential heat treating)?
Lew had a pedang with a blade that quite strongly resembled a Japanese sword blade (
http://vikingsword.com/lew/w0132/w0132.html). Ultimately, XRF disclosed a composition much more consistent with typical Indonesian blades than Japanese ones.
In any case, I understand why your small knife would be a favorite