I thought some of you guys might be able to use this idea. My Z560 had an unused SATA port but no room inside for another drive. I used a SATA to eSATA PCI slot plate adapter to get an eSATA port on the rear panel. I'll be using this for a 2TB external HDD, but it should also work for a multi-drive enclosure with eSATA interface. I'd like to build a RAID array someday, and this makes it easy to upgrade in the future.

 There's just enough room for the eSATA jack next to the wireless card. That panel is also removable which makes it easier to cut the hole without damaging the machine.