AFAIK The only 126 available is Ferania (did I spell that right?).
Depending on the camera you could cut open a case and refill it with either 35mm or cut down 120. Th eonly problem are the perforations - like 110, 126 needs 1 perf between each frame. Some camera's need this hole - others don't. Experiment and see...
127 is right, the only 126 film still made is Ferrania sometimes labelled Solaris which is a colour print film. I don't think black & white 126 films have been made for around 15 years, the last I came across were Kodak's Verichrome Pan and the Spanish made Negra Negrapan 21 (of the latter I still have a few rolls in the freezer - not for sale!)