jimc:
my list begins with Paulette Goddard with 4 that I know of: REAP THE WILD WIND; NORTHWEST MOUNTED POLICE; SUDDENLY LAST SUMMER(although this was only a posed publicity shot and there is no spanking in the movie itself)
Paulette wasn't in
Suddenly, Last Summer; the female stars there were Elizabeth Taylor and Katharine Hepburn.
Martha Hyer got spanked twice, in two B-westerns:
Thunder Mountain (1947) and
Rustlers (1949). By the same guy, too - it was Tim Holt both times, each time because she'd been unwise enough to pull a gun on him. Some gals never learn....