If you really have a BUNCH, get a SAS disk expander. I have 2; one 2.5" with 25 slots, and one 3.5" with 16 slots. The 2.5" all loaded (I have 20*600GB + 5*3.8TB in) uses about 50W in normal usage. It is a bit noisy of course, but not *that bad*... Also cheap s/h. You just need a HBA card. The 3.5 I turn on to do whole backup, it has 3TB disk in there and thats *largely* enough to image all my stuff several times, I only turn it on via a PDU when I need it.
If you only have like 10 ish, in my workstation I use a 8 bay SAS 2.5" "icybox" that fits in 2*5.25" chassis bay... In that machine I use a Dell Perc raid card and run 8*1.8TB 12Gbs disks for around 10TB total storage in there.
SAS disks are cheap as chips refurbed, super reliable.