Supermicro JBOD? For 3.5", can have 12 in 2U, 16 in 3U, and 24 in 4U. If 2.5", looking at 24 drives in 2U. Can often find good deals on chassis, though the SAS3 backplanes aren't as common as anything 6gbit. What's your budget?
Can always take the direct connect A-style backplane and just connect a sas3 HBA to the backplane and use sas3 disks, think it negotiates properly. Guess I could check, I have that same exact setup. :-D
EDIT: Yep my sas3 disks look good in that A-style direct connect scenario. (da1-4, husmm1680 connected to a LSI 9300-8i on a SC216 w/ A-style backplane) :-D
@whitey if each drive is directly attached to a hba controller without a backplane then I believe you are unable to attach these drives to second host ? or i'm missing something ? I would like these drives to be "dual-homed", attached to two hosts at the same time. Each host having own LSI 3008 hba controller.