If they manage to get 12TB on a single board, running at a fraction of the power of a salvo of 15K SAS drives then they could charge whatever they want to, that is just mind-blowingly amazing!
It would take 40 300GB 10K or 15K drives to reach 12TB of data. Assuming a throughput of 150MB/s/drive that would be 6GB/s of sequential read/write performance, which will beat this card (assuming it is a PCIe2 8x slot which caps out at 4GB/s throughput). For IOPS, this card (and even the R4 cards) would easily beat 40 SAS drives at 200IOPS each (for a total of 8,000IOPS vs the R4's 410,000 IOPS, and I am sure the R5 is faster). If this is a PCIe3 card with 8GB/s of bandwidth available then it will be even faster still! Plus when you figure that this single magical card could replace 40 physical HDDs... that's a lot of power, and a ton of space saved!
Now for price, 40 15K 300GB drives can be found on newegg for ~$450ea (I am assuming also this price is also inflated due to the floods just like the consumer drives are), totaling $18,000. The R4 3.2TB drive starts at $20,000, which means a 12TB drive would be ~$50-60,000, which is 3x the price of the SAS solution, and a rough equivilant in performance in sequential throughput. For IOPS however (again using the R4 specs as we do not know what the R5 is yet, except that it will be better) you get .4IOPS/$ with the SAS setup, and 6.8IOPS/$ with the R5 for the same amount of storage space, but a small fraction of power usage, and even smaller fraction of physical space used. I think that says it all for the pro markets, if this is anywhere near $60,000 for 12TB (or even north of $100,000) it would be more than worth the cost compared to the performance gained. Simply amazing!