It's never attractive. Ever. The infrequency of it pretty much brings up an ingrained semblance to bald men every time for me. It's the tomboy look taken too far.
Gonna have to go with no. I don't think I've ever seen a woman with a shaved head that looks better bald than she would/does with hair. She may look fine bald, but I don't think she would look better without hair, in my opinion.