Richard posted a picture of the spanking Evelyn Venable receives from Victor Jory a while ago.
Time to add the clip for Streamline Express (1935)!
Not quite as old, but I guess you could still call it vintage. A scene from the 1975 adult movie The Journey of O.
A switching including a maid, but with a nice twist!
Credits for finding, creating and uploading this clip go to ataru!