One of the first film offers the Beatles received was to do a cameo in a movie called The Yellow Teddy Bears, a lurid drama about teen sex and pregnancy set in an all-girls school in the English suburbs. The boys were asked to play a band that backs up one of the film's male characters, who dreams of being a pop star. Because director Robert Hartford-Davis wanted to write all the music the Beatles were meant to play in the film himself, they declined (another Beat group called the Embers took their place).To which I can only add -- wow. Which is to say that, obviously, history might have been changed in unfathomable ways had the Fabs actually gotten involved with this project.
The film itself appears to be pretty much of a sexploitation period piece -- director Hartford-Davis seems to have had a rather undistinguished career, save for the 1965 sci-fi musical classic Gonks Go Beat -- but if you're curious you can order it from Amazon over here.
As for the Embers, the pop combo that took the place of the Beatles in the film, I can find no information whatsoever.