I'm starting to think I might have better luck having a pre-built some code with some poor practices and asking a candidate to refactor and improve it- evaluating their ability to at least know what clean code is supposed to look like.
That being said, I'm not willing to give up my whiteboard code interviews yet- they are too useful a filter. I still get candidates that sound fine talking about their previous experience and then say things like "oh man, its been a while since I've used arrays" when asked to code.