In my opinion, I think you should stick with Knight of Zero.
You were so convincing and totally epic as Knight of Rounds Suzaku that I'm having trouble seeing you cosplay as anything but Suzaku (Sorry for typecasting you :P)
As for the whole "is it appropriate for the B&W Ball" thing: as long as it has the cape, KoZ is definitely formal attire.
Then again, I'm a guy who wears aloha t-shirts to funerals and whose Zero cosplay is the most formal attire I've ever owned in my life, so I may not be the best person to address this issue.
You were so convincing and totally epic as Knight of Rounds Suzaku that I'm having trouble seeing you cosplay as anything but Suzaku (Sorry for typecasting you :P)
As for the whole "is it appropriate for the B&W Ball" thing: as long as it has the cape, KoZ is definitely formal attire.
Then again, I'm a guy who wears aloha t-shirts to funerals and whose Zero cosplay is the most formal attire I've ever owned in my life, so I may not be the best person to address this issue.