Here's a trick you can use.

For tech people, search GitHub for people producing code using the tools you require.

For COO people, review videos of people giving talks at industry conferences + tradeshows related to skills you require.

For CMO look at WordPress.tv + conference videos for people with both tech skills + marketing skills.

Sometimes having a CTO with marketing skills is far better than having CMO with tech skills.

Another test/question for CMOs...

"How much are you currently grossing every month from your personal projects."

If you're looking for competent CMO, look for someone making a truck load of money... without ever leaving their house... Then be prepared to pay them even more to get them out of their house.