I know Cabela's used to sell them. I think they were the only US importer. They dont seem be available since Cabela's no longer carries them.

I had one in 9.3x74R (SxS). It was a great Pig gun, and had a decent price. I think the 45-70 and 9.3 were $3000 and the Nitro cartridge versions were $5000. I now some guys didnt like the way they were regulated and the stock was "dipped" to look like well figured wood; but they were a poor mans entry to a true double.