In 20 years of sneaking through gunshops in Texas, I never saw a double rifle...saw just some British shotguns of all grades, mostly 2 1/2" chamered 12's, and two genuine Rigby bolt actions chambered in .416. And a mint condition original 1874 Sharps for $1200 and a mint condition 1886 Winchester .40-82 for $450, both of which I still regret not buying....
That was it to my recollection as far as the good stuff...
Never saw a double rifle until I specifically started hunting for one in specialty shops.
Saw a double rifle suitable for stomping elephants in a shop in Australia though as well as a ton of neato surplus .303 Enfields priced at only $70 AU in a shop in southwestern Vic..unfortunately the shipping and paperwork mess would likely have made the Enfields too pricy to bring to the USA. Strangely I saw no elephants near there so I still wonder how the double rifle made it into that shop...