I wonder what problems a 5 person startup is trying to tackle that they can't find technical talent worth interviewing... just from the way you wrote it already makes me feel like a place I wouldn't want to work for
Once you start interviewing people, you will realize how utterly incompetent most of them are. I am talking about people with multiple years of full-time experience in the field and a relevant degree who cannot even implement a basic FizzBuzz. And I am not exaggerating it for comedic value, I legitimately met many people like that by now. Prior to seeing this myself, I could've sworn this was just a joke people used to describe incompetent people, but this is real. And being able to pass FizzBuzz doesn't even scratch the surface of being competent, but a lot of people cannot manage to get past that stage.
People with experience have more dignity than to perform a dog-and-pony show for some startup on a whiteboard. Remember, in this market you need them more than they need you.
Every single engineer who was or is employed at any big tech company has went through whiteboard interviews. If you are trying to imply that big tech companies cannot manage to attract experienced people, then I question the validity of that.
Have you considered the possibility that you're asking the wrong questions? Or perhaps your organization isn't good at identifying candidates with low skills but high potential?
Why waste time interviewing incompetent people?
Just ask for code samples (github, stackoverflow, anything else) and make a 5-minute screening call via Skype to filter out incompetent people.
I'm sure all of them can implement FizzBuzz, just not on the interview under pressure. It has absolutely nothing to do with competence, but understanding that requires just a little bit of background in human psychology.