https://www.kncminer.com/products/mercury$ 1,995 + 204$ shipping = $ 2,199.00
The final specifications for this device are being ironed out now but we can confirm the following.
100GH/s per device.
Maximum 250w
28nm standard cell ASIC Chips (which are being designed exclusively for KnCMiner by ORSoC).
Modular Design allowing for expansion at a later date.
Embeded Linux device to allow for standalone mining.
Shipment begins in September
This device will require an ATX power supply
Am not sure if anyone can profit from this.
With thousands of avalon chips starting scheduled to come out in June, July and August. (my estimate based on block chain address calculation is ~ 240K chips)
i.e 240k * 242 mh/s = ~ 58 Th/s to be added to the network by avalon alone in well before September. please note this doesn't include ASICMINER / BFL + Pinwheel's 1.2 th/s bitfury :-) (No offense PW. Am proud of you mate).
So am sensing about 100 Mil difficulty for September.
Keeping that in mind, ROI will be about 90 days. Again, price of the btc is also a factor here. But i don't see that changing drastically since the main reason people are buying btc now is to trade. We need more businesses where we can use btc's to exchange for goods.