Here are a couple of additions to my earlier list:
Friday Jones, from the novel Friday, by Robert A. HeinleinShe's described as an "Artificial Person," which means a genetically-engineered 'superwoman' with greater strength, speed, stamina and intelligence than an ordinary human, so she would have little trouble soundly spanking a normal person. She obviously believes in corporal correction, since the book's conclusion refers briefly to Friday administering spankings to her own children.
Fanny Hill, from the early erotic classic Memoirs of a Woman of Pleasure, by John ClelandShe's a young woman who ends up forced to support herself as a prostitute, which involves various sexual acts considered 'perverted' at that time (the novel was published in 1748), including one scene with a male client in which she both administers and then undergoes a thorough bare-bottom lashing. (The butt-whipping Fanny delivers is rather severe, the one she receives not quite as much so, but still intensive enough to make her extremely uncomfortable.)
I would consider
Memoirs of a Woman of Pleasure, which was the subject of a famous U.S. Supreme Court decision which legally defined the meaning of obscenity, to be mainstream erotica for its era. Although it isn't a spanking-oriented novel, the one 'flagellation' scene is nicely described...

--C.K.