I just got this case, and says that you can mount 5 drives, http://www.newegg.com/Product/Product.aspx?Item=N82E16811353026 having a problem seeing where there are SLOTS to put more then TWO harddrivesThere is lots of room.
Three bays are the 5.25 form used for CD/DVD drives. And older HDD.
You can either get a 5.25 HDD or use an adapter.

About $6 from on-line sellers.



The pictures show a drive cage that appears to hold 3 drives.So basically, I would have to get BAY adapters to.  This is what they said on the spec's of there page, Expansion

External 5.25" Drive Bays
    2

Internal 3.5" Drive Bays
    5

Internal 2.5" Drive Bays
    2

Expansion Slots
    7Here is what I saw:

Last year it was said that the 5.25 inch might come back.
http://www.kitguru.net/components/hard-drives/anton-shilov/seagate-5-25-inch-hard-disk-drives-could-return-to-datacentres/
Quote

The amount of data that modern hyper-scale datacentres need to store is already overwhelming and it continues to grow exponentially. In the recent years many hard drive makers introduced multiple ways to increase capacities of storage devices, but things like shingled magnetic recording as well as helium-filled hard drives may not be the only ways to boost HDD capacities. Seagate Technology hints that the industry could return 5.25” hard disk drives to the market, which will dramatically increase per-HDD capacity, something that will be extremely useful for cold data storage applications