The film in a 126 cartridge is in fact 35mm and will fit in any 35 mm processing reel; any mini-lab can process it (to negatives) if they're willing to handle film that's not in a standard 35 mm or APS cassette. That requires they have the magazine setup which, in turn, would let them make negatives (even if not prints or scans) from *any* C-41 still film from Minox up to whatever will physically fit into the machine (which would likely include 122/124, or at the least 116/616, since the leader cards are something like 90 mm wide).