If you can't get something suitable it might be worth finding a local maker of flight cases for musical instruments and asking them to make you one up. That is what I did for transporting my Blaser by air as I wasn't convinced that the Blaser case was robust enough to cope with the attentions of the baggage handlers. A custom solution may not be cheap but you could be sure you are getting what you need.
Not sure about that, mine will easily take an X-Bolt, Pess T12 and a 50mm scope in high mounts.
The liner may be a little tight, but I find a thin fleece lined gun slip minus the strap a better option anyway, even leaves room for a set of sticks.