I think the 810 is about the same size as the 810A, except for the motherboard mounting location.Is the 810, which is meant for a mini-ITX board, comparable to the 810A? The only reason I ask is because I was thinking about getting the Supermicro-X10SDV-4C-TLN4F-O for its power efficiency, but I also really like the U-NAS chassis look.
I have the TLN2F (dual 10g) motherboard that i've been using in the 800 - which is slightly more compact than either of the 810's. It worked fine in there - Perfectly fine. The only reason why I got the 810A was I needed more network ports for all my vswitches in hindsight I should've gotten the TLN4F instead.
The Supermicro X10SDV-7TP4F would be more appropriate for this chassis.