Sure have. I have held in my hands a James Purdey & Sons 4 bore double rifle. The rifle weighed around 20 pounds. Only a handful were made. It was owned by Ray Meyer, who has long since left us. Ray hunted extensively in Africa and was a good friend of Elmer Keith's. The picture was taken in the mid 80s when I was a LOT younger.
BTW, Ray also owned that Thomas bland 4 bore that broke my collar bone.
And he owned another double rifle that gave me goose bumps just looking at it. It was an Army/Navy .577 3" Nitro Express. The Army/Navy guns were big game hunting rifles that were gifted to high ranking officers in the Colonial days, when "The sun never set on the British Empire." They were manufactured by the various high end British gunmakers. They were unmarked with the manufacturers name, I suppose to prevent any squabbling over who got a Purdey and who only got a Thomas Bland. Ray showed me where and what to look for because of differences in finish and polishing techniques. The one I held was made by Holland & Holland. I don't have a pic of that one, but I did get the honor and privilege (and pain) of shooting it. It definitely let's you know about it when you pulled the trigger.