Hi all and thanks to Korbman for the analysis,
Here some of my thoughts on this matter.
An FPGA running at 800 MH/s would cost around $800 running at 80 Watt.
The BFL ASIC SC presumably running 40 GH/s costs $1300 running at 100 Watt (uncertain).
While neglecting the difference in electricity consumption, the ratio ASIC to FPGA would be:
(40000/1300)/(800/800) = 30.8 times the capacity per dollar on purchase.
If we assume the current network capacity of 20TH/s is running on FPGA and invested hardware would be completely replaced per dollar by ASIC, the resulting network capacity would be around 600 TH/s.
BFL would need to sell 15000 SC's (or 600 SC rigs) for the miners to achieve this enormous figure.
Using TP's Bitcoin calculator, I would reach break even after almost 500 days:
http://bit.ly/P8lEMEHaving said that. This figure will probably not be reached in a short period. Miners have to invest in hardware again. Miners have to ensure more bandwidth. Making the entire operation more like running a business.
BFL probably won't be able to ship 600 rigs, or the equivalent in single SC's in a short period. Resulting in sales for the amount of 600*$30k = $18M.
Then again, I think Korbman's TH/s prediction (143 TH/s) will be reached in 2013 easily.
Challenge me :-)
http://betsofbitco.in/item?id=612 (difficulty will exceed 8000000 on March 1st, 2013)