Given that Malaya was formerly controlled by the British, and present-day Indonesia formerly controlled by the Dutch, I think it may also be reasonable that there are more Sumatran and (other Indonesian) kerises in Holland than Malayan kerises.
Yes, this keris would not look odd in a Sumatran keris sheath. The only question is what is the appropriate style, given that there are many many different Sumatran sheath styles.
I have seen similar blades in Minang style sheaths (I'm not suggesting you to do that), but I think it will not look odd if it had the sheath of the sepokal keris I posted a few days ago.
Happy hunting for the sheath!