Data10. The example company that I mentioned above is in the silicon valley and they paid for travel costs (both for the onsite interviews and for relocating for the summer). I’m guessing that only about 25% of their interns this summer came from California schools. So, in that instance, location appeared to have little bearing.
I suspect that the disproportionate representation of elite top tier colleges was because they hired relatively few interns (only 20) compared to what I hear is hundreds at Google and Facebook – and yet the difficulty of their technical interviews was harder than those two companies ( according to some interns who posted on Quora).
But I agree that most tech companies will take interns from any college – once the interns have been identified to meet their standards…programming contests can be a particularly useful identifier.