I'd say a good price point would be around $1500 to $2000 dollars....

First although novel it's not the most desirable action and second I'd be suspicious as to why the chambers were sleeved from 10 to 12. This is easily accomplished with Chamber/Gauge Mates.

Could the chambers have been badly pitted ?

Honestly I've never saw a Gun on their website that wasn't astronomically over priced.