Nobody has mentioned these, but, Mexico built a rotating barrel .45acp based on the 1911 called an "Obregon"
http://world.guns.ru/handguns/hg/mex/obregon-e.html which could probably be redesigned for double stack capability.
Russia built a break open .357mag called the Izmech MP-412 Rex(not available for US import due to Clinton gun ban)
http://world.guns.ru/handguns/double-action-revolvers/rus/izhmeh-mp-412-e.html I would love to have one of these in .357mag and/or .44mag.
China built a .45acp version of the C-96 called the "Shanxi type 17" (this is copied from Wikipedia)
Shanxi Type 17 (.45 ACP)[edit source]
During the Warlord era of Chinese History in the early 20th century, the province of Shanxi was ruled by warlord Yen Hsi-shan, who had established a modern arms factory in his capital city of Taiyuan. Yen was equipping his troops with a locally produced copy of the Thompson sub machine gun, chambered for the .45 ACP cartridge, but was experiencing supply difficulties as his troops' sidearms were 7.63mm calibre C96 handguns.[20]
Yen's solution was to produce a .45 ACP caliber version of the C96, thus standardizing ammunition and making supply logistics easier.[20] Designated Type 17, production on the .45 caliber handgun began in 1929 at the Taiyuan Arsenal. They are inscribed (in Chinese) "Type 17" on the left hand side of the gun, and "Republic Year Eighteen, Made in Shansi" on the right hand side.[20] They were issued (along with Thompson SMGs) to railway guards in the province as defense against bandits and other warlords.
Besides being chambered for a larger cartridge, the Shanxi .45 pistols are noticeably bigger than their 7.63mm counterparts, with the 10-round magazine extending below the trigger guard. It was loaded using two 5-round stripper clips rather than the single 10-round stripper clips of the standard 7.63mm Mauser.
Most of the Shanxi .45 pistols were melted down after the Communist victory in the Chinese Civil War, largely due to their odd caliber for Chinese Communist standards, but a few examples were exported overseas for sale on the commercial market.[20] Approximately 8,500 Shanxi .45 caliber Broomhandle pistols are believed to have been produced by the Taiyuan Arsenal, but there is some debate as to how many of the Shanxi .45 caliber Broomhandle pistols currently on the commercial market were actually produced for Yen's troops, and how many are more recent productions for the US collectors' market.
Just food for thought.