She did mention that Pulse only pays for code or projects that would be used in production. Agreed, paying people for all interviews would not scale. :)
Ouch, that may be a serious problem. Are all of the projects intended "for production"? That is, are there some projects that Pulse won't pay for even if they're completed successfully (internal stuff)?
Now you're excluding all candidates who aren't willing to spend some time (a week?) working for what might be free. And some of these candidates will be the highly-skilled programmers you'd love to have, but who won't be willing to jump through hoops when they can easily get a job elsewhere with fewer hoops.