I, too, have seen the bald male Northern Cardinal. I have a whole subfolder full of 'em.

The research I did, actually matched to what I have been seeing. I will have to find where I got my info, but I have witnessed this every summer, in July almost all of the males go bald, not just a few. I read that this is a natural part of their feather cycle. Like the mourning dove molts in the fall, the male Northern Cardinal molts it's head feathers in July. (Just about everyone I know who birds here in NC have witnessed this at this time of year.)
I have not heard it was caused by parasites.
I have seen the phrase "When they're moltin', they're revoltin'." to refer to the bald male cardinals, which pretty much sums it up.
As for a bird of a cardinal shape and coloring, with black head feathers, and is not bald, I have never seen a bird like that.