Wow! Just found this thread. I'm a happy DACmini owner and would love to own an HiFi-M8 if it is available with a 4-pin XLR jack.
I recently rewired most of my reference phones (LCD-2 r1, LCD-2 r2, HD800, HD650, HD580) to 4-pin XLR after the purchase of a Bryston BHA-1 and Schiit Mjolnir. The M8 would only make sense for me if it had a 4-pin XLR as I wouldn't want to mess with 3-pin to 4-pin adapters. I hope the 4-pin version becomes a production version.
What a great company!