This keris recently ended on eBay. I was intrigued by it's hilt, which to my eyes appears to be a more figurative representation of the Jawa Demam. I have never seen this form so humanized, though we do certainly see less abstracted forms, especially out of Sumatra. Paul de Souza comments on his website that while some have claimed the Jawa Demam form to be an abstracted Garuda, there is some evidence that it is the form of a man.
http://home.pacific.net.sg/~dspf/hilt.html
Is this hilt the proof?
On the other hand, i don't think this hilt is particularly old so it could be a more modern revisioning of supposed origin.