IIRC a member of a Norwegian gun forum, built a rifle using that action. I think in 577 T-rex.

The gunsmith is one of the better known among Norwegian shooters and does good work.
I agree, I wouldn't pay $10k for that action either, but just for reference, if I were to import a standard $4500 AHR DG rifle to Norway, the final cost after export fees, tax etc would be approx. 6600-6700....
A Heym Express bolt gun starts at about $10k as well IF i remember correctly.
So in a way, the price isn't that bad in that context.