Now 2TB SAS drives are within ~10% the price of 2TB SATA drives ...

(7200 RPM 3.5 inch) SAS has a few specific advantages over (7200 RPM 3.5 inch) SATA, not enough to justify a 50% premium for storage clusters and many storage apps. A 10%? Yeah, I think that could work. I’d like to build a few more of these. Definitely.