Well, my calculations used BFL's Mini Rig SC, which was $20 per GH/s before they increased prices ($30k for 1,500 GH/s).
You would certainly need to fab your own ASICs, and at that volume economies of scale would come into play, so I don't think $20 per GH/s, or even less, is an unreasonable estimate.
Current hash rate is 65,000 GH/s (I think calculated around 40 or 50), so 65,000 * $20 = $1.3M. 50x that would be $65M.
You would certainly need to fab your own ASICs, and at that volume economies of scale would come into play, so I don't think $20 per GH/s, or even less, is an unreasonable estimate.
Current hash rate is 65,000 GH/s (I think calculated around 40 or 50), so 65,000 * $20 = $1.3M. 50x that would be $65M.