Pe Reivers - I was going to ask you if you know specifically about this wood?  I have used the props and they seem to have about the same density as the Xoar beechwood props.  I see you are a dealer for Xoar though - I think they are very good props, but I don't know that the Zelkova wood has any less strength than the beechwood. 

I did a quick test of putting a weight with a pressure point on each and the indenation was similar.  If I break a prop maybe I"ll do more in depth comparison.