Yes. Some of the singles listed could probably be rifled. There were a couple of 8 single rifles floating around the US for sale but I don't know if they sold or not. A Holland single rifle 8 with good provenance sold at Holt's Auction, I think a few years back for 17,000.00 US. There is also quite a niche following here in the US for big bore single shotguns. The bigger, heavier more unusual the better.