(1) set up a non-government board consisting of credible VCs, entrepreneurs, and lawyers to vet applicants.
It probably is a better solution than what PG proposed in his original essay. "let the market decide. Startup investors work hard to find the best startups. The government could not do better than to piggyback on their expertise, and use investment by recognized startup investors as the test of whether a company was a real startup."
PG's version would eliminate anyone who would bootstrap a startup without external funding. Brad's is a little inclusive.
I would rather prefer to leave it at "let the market decide."
Any interesting ideas as to how you could convert that statement into an actionable policy for immigration authorities to follow?