So, after way way way way way too much research, I ended up going with the 5TB version of this from Costco for $115 + tax.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822179031&cm_re=seagate_hub-_-22-179-031-_-Product
I'm giving up USB power, but it's supposed to be very fast...