In about 2010 when I decided to start making the magnets myself, I found that left me unable to offer shaped magnets. Well, they are back now, and are the same high quality as the rectangular sizes.
These magnets are approximately 4 inches in diameter, have a glossy finish, are about 30mil thick, and are circularly awesome.
Check out some designs:
http://savethedateoriginals.com/RoundMagnetDesigns.php
And, by the way, these will be on sale during November. To celebrate the return... 20% off!