Hello Charles,
a real beauty, I am green with envy!
There seems to be some very beautiful examples of this knives out there. But still think that this knives wrong labeled as siraui. Here is another nice one:
http://www.vikingsword.com/vb/showth...ghlight=siraui 
Hope that we will be able to solve this mystery about this knives one day in the future.
Regards,
Detlef