Saw a BMC on the pics you shared. Is there IPMI functionality on these boards?Works great. Not having a VGA out is kind of tricky though. BIOS setup is not a problem - it is redirected to a serial port. For the OS install I just pulled the SSD DOM, put it into another PC, installed OS (I think I used Ubuntu but I do not see why anything else wouldn't work as well) and put it back - done.
The best part - you only need one per NAS. So if you get a deal on an enclosure with 2 controllers - you could build 2 systems. Just add another SBB enclosure. DS4243 would work just fine.