I think that, in general, fantasy dwarves are all basically derived from Tolkien's works. That said, many people are psychologically against females with beards
so people tend to break this rule here and there (especially in the CRPGs of Japan and such, but also in America/UK).
Still, I have noticed bearded female dwarves in various AD&D supplements (notably Forgotten Realms), including notes about female dwarves who want to hide their sex from male dwarves (by growing long beards and wearing male clothing) and pictures of dwarven priests (priestesses tend to have beards/moustaches, although many of them had at least the top or bottom shaved off).
My favorite fantasy artist, Larry Elmore, doesn't seem to have drawn any female bearded dwarves, though