I ended up going the opposite. Went from a 4U rack mount Chenbro and 24 drive DAS to the UNAS 810a and no regrets at all.I gave up waiting after months of no info on this case and decided to do a Supermicro 846 build after watching a Youtube video of a guy replacing all the fans with Noctuas. Basically went in the opposite direction of a small compact NAS.
While I'm not 100% sure with the direction they are taking these, they historically use 7 pin for disk and molex for power.I found pics here: Silverstone Cases on Display at CES 2019 Including an All New Raven Prototype
For day 1 purchase it should come with SAS/SATA backplate with MiniSAS and power connectors. I have a feeling we'll see empty chassis and have to plug 16 connectors (8 data + 8 power) to make it work.
I'm not very excited about U-NAS 810A, (mATX, 8xHDD), because of that and bad cooling in that case. Hope Silverstone can address that.
One notable line from the linked page: 'All the cases shown here are in their final forms. However, availability and pricing were not revealed during our visit.'