Looks interesting, no caddies is an issue though, from the manual it looks like the caddy has a sata interface into the chassis. Hopefully its not anything proprietary
Data Direct Networks DDN Storage Scaler 6000 SS6000 HDD Array SAS / SATA JBOD | eBay
Data Direct Networks DDN Storage Scaler 6000 SS6000 HDD Array SAS / SATA JBOD | eBay