Brandy, I just googled pancake motor for the picture. I can't help with a definitive source. One problem you might have is, pancake motors are much larger in diameter than typical cylindrical motors. Even if you find one the same diameter as the Pullmor consider that the Pullmor shaft is off center. The Pancake motor will sit lower.
This site is a great source for motors of all shapes and sizes. See if they have something that will work for you.
Pete