You asked about this before. 520 bytes sectors do not exist, variable sectors do not exist except in software RAID designs, like ZFS. Where on earth did you get this information?
If you really want a SAS drive (it won't be fast; trust me) you can use any PCI-express SAS controller; try looking at Highpoint for example they make affordable products. LSI/3ware/Adaptec might do as well.