I see GitPay and Bountysource, .. both use fiat only. And require doxing yourself (and being sent a 1099, for those in the U.S.).
I can see that being a significant factor that holds back the use of bitcoin for freelancing, at least at the level where the employer hires/contracts with the freelancer directly, due to reporting and withholding requirements for the employer. And that's not just in the U.S. where that is a problem.