Do you need internal storage? If you are worried about your SLI setup and spacing your better option will be to look at a NAS. Although they can be expensive if you are to get a decent one.
http://www.newegg.com/Product/Produc...82E16822240035
Is what I use at home it has USB 2.0 and Gigabit ethernet ports and room to fit 5 drives. If you aren't very good (Or like in my case just lazy) with computers and RAID these are the way to go, it will automatically configure RAID to give you the most storage with complete data redundancy so all you have to do is literally just slot the drives into it.