In 2008, I was hired to work on a tech startup from Australia, while I was living in Brazil. After I went through an initial quiz and a few interviews, they wer

In 2008, I was hired to work on a tech startup from Australia, while I was living in Brazil. After I went through an initial quiz and a few interviews, they were willing to give me a shot by giving me (and paying for) a small project to code. Only after succeeding at it, they hired me, sponsored my visa and paid for all the relocation costs. In your case, I really think this approach would be a good bet in cases that the YC company is willing to sponsor the visa from the potential employee, so giving him a paid project before even flying him, might be a good filter.