Yes, it is a 410/45LC combo derringer, and runs about $80-$100.
They didn't. The barrel swung out to the side. 1926-35
The company is the propery of Sylvia and Wayne Daniels. "Leinad" is his last name spelled backwards. They are currently not producing any and they don't speak about their future plans. YES! Leinad Derringers are still made. I just bought one ( 8/2/2010) They are made under many names ( Leinad, FMJ , Cobray and a few others ) They are available in double and single barrel in .45LC/.410 and .451 black powder. ( barrels are interchangeable between BP and Smokless models BTW. Just check your state and local laws ) They can be bought from Practicaltactical.net or KYimports.com.
frame, barrel, sights, grips
No, if it was designed to be a single shot, it's a single shot. It needs to be reloaded after each shot.
Not familiar with a Hawes Dueling pistol. However, they did make a top break .22 Favorite Single Shot Target Pistol- a reproduction of the Stevens #35, chromed fame, blued barrel. $100-175, depending on condition, made 1968-76.
One can make a pistol much larger than it needs to be, maybe even having an extra-long barrel would make a pistol larger, technically. I'll assume you mean the barrel diameter. Although it would seem that a .380 and .38 would have the same barrel diameter, namely, 38/100th of an inch, that is not usually very accurate. The .380 ACP has an actual barrel diameter of about .35 caliber, or 35/100th of an inch. The .38 Special has a barrel diameter of .357 caliber, or 35.7/100th of an inch. So the .38 Special has an ever so slightly larger diameter.
I do not personally, but yes, there is a single shot rifle that can have the rifle barrel replaced with a shotgun barrel.
Remington did not make a 44 cal double barrel pistol. The did however make a 41 cal (rimfire) the double derringer. (model 95) There's 3 type's, 5 models, and at least 15 variations some of which are quite valuable.
Not published in any reference.
1837
yes they made a martini action single barrel shotgun 12gauge it is cheap around £100 but it has a huge amount of recoil you can buy them on guntrader.com
I'm not aware of any that exist, but for enough money I'm sure you could get a gunsmith to make one for you. My grandfather had a single shot 22/410 over and under pistol he kept in a holster mounted to the door of his pickup. Barrel was about 14-16" long. Believe it was a Stevens Game Getter.