So, I've been researching OCP SAS cards and finally stumbled upon a few models I am pretty sure will fit as is.
Tyan has one of the best published "Storage Mezzanine cards" guides. Too bad their tyan.com DNS server seems to be hacked (lots of porn, giveaways, contests - all garbage URL Links) in sub-domains like "
www.giveaway.tyan.com", "
www.ww.tyan.com" <- tries to load a Javascript virus, and so on. If you manually fix the URL, the regular site works.
Unfortunately, I can't find many Tyan SAS controllers on ebay. Maybe someone here knows a cheap source? Listed below are the models that should work without issue.
SAS3 8-port
StorageMezz M7076-3008-8I M7076-3008-8I
support.tyan.com
Unfortunately, the heatsink may interfere with the card you insert into the PCIe riser in that area. Maybe, maybe not...
SAS2/SATA6 (if you can use slower)
HBA M7094-2308-8I M7094-2308-8I
www.tyan.com
Gigabyte also had some OP SAS3 cards. however, their versions are much longer (out of OCP spec) and seems it would interfere with the TPM module as well as one of the SATA ports (and would block BOTH sata ports!).
I think I am done searching for SAS OCP cards as this point and will just use a normal PCIe version for now, until I get rid of the SAS drives.