I found some really nice looking magnets on alibaba, they are about 5-6 cm long, and 1 cm wide OD, and about 1 cm thick,
And they are coated black with epoxy, A rather nice touch. But, correspondence with what ever corp it is in guangzton or somthing like that
has proven to be most difficult, Showing a picture with dimensions seems to still go right over their head... :/ sigh