Here is a great photo from World War II, showing a fleet of Boeing B-29s being built in the assembly facilities at Wichita, Kansas. This isn’t quite as good as this colorized image of women building the B-17.

Source: Detroit Public Library
Below is the detailed description of the image:
View of Boeing B-29 Superfortress bomber aircraft assembly lines at the Boeing Airplane Company’s Wichita, Kansas plant. Label on back: “From: Boeing Airplane Company, Wichita, Kansas. Photo no. BW-23975. The immense scope of Boeing-Wichita’s mass production job on the world’s greatest warplane is graphically illustrated in this cross-section view of the B-29 Superfortress assembly lines in the Wichita Division bomber plant of Boeing Airplane company. The same Boeing multiline system of production that sent thousands of Boeing B-17 Flying Fortresses into battle has been adapted to the Superfortress in such a manner that Boeing-Wichita has consistently met–sometimes even exceeded–delivery schedules set up by the Army Air Forces. In fact, at the request of the AAF, these schedules are now in process of sharp upward revision in the Wichita plants. For more than a year in production on the B29, Boeing-Wichita has turned out the vast majority of the great aerial dreadnaughts which so far have been operating against Japan. Up to the present time Boeing-Wichita is the only manufacturing facility in the Superfortress program carrying out full mass production requirements on the B-29.” Stamped on back: “Photo courtesy of Boeing Airplane Co., Wichita Division, Wichita, Kans. Please credit Boeing-Wichita photo.” Handwritten on back: “Aircraft–Bombers (Parts & assembly).”
Here’s another great view from that same factory.

Source: Detroit Public Library
And here is the detailed description:
View of nose sections of Boeing B-29 Superfortress bomber aircraft at the Boeing Airplane Company’s Wichita, Kansas plant. Label on back: “Trouble for Japan! Two rows of sleek, glistening nose sections on Boeing B-29 Superfortresses are shown here on the assembly lines of Boeing Airplane Company’s Wichita, Kansas plant. In the left background are huge double bomb bay sections while in the distance may be seen nearly-completed B-29’s on their way to join sister ships which have gone before and are now at distant bases carrying out their assignments against Japan. A systematic schedule of production cycles whereby sections making up the Superfortress advance one position in a mass movement taking place at the end of each six hours and forty minutes has placed bomber assembly lines on a clocklike precision basis at Wichita. The movement of the production floor starts at exactly the same instant, each section going forward one position. The system not only unifies all phases of production and eliminates confusion but also establishes at all times the exact location and amount of progress on every B-29 unit. It takes about two minutes to complete the mass movement on the assembly floor. As the first producing plant in one of the largest production programs of the war, Boeing’s Wichita Division has been turning out the big bombers for more than a year. Switching over from the manufacture of B-17 Flying Fortresses, Boeing’s plants in Seattle and Renton, Washington are now producing the Superfortress, and the Bell plant in Georgia and the Martin plant in Nebraska are also building the Boeing-designed B-29.” Stamped on back: “Photo courtesy of Boeing Airplane Co., Wichita Division, Wichita, Kans. Please credit Boeing Airplane Co. photo.” Handwritten on back: “Aircraft–Bombers (Parts & assembly).”