Just a few observations for you on this.
The Xpatch is intended for a recording environment, so it uses electronic buffering and switching, and is a mono 16x16 matrix.
I don't know if they switch balanced, but they probably have op amp buffers on the inputs and outputs then route unbalanced in between. Electronic switches nowadays are quite good, but they're not in the same calibre as relays.
Cost wise a 16:1 electronic switch comes in a small SMT package and costs about $1 in qty, and the equivalent 16 relays cost about $20 and take about 100cm sq of board space plus lots of power.
A 16x16 mono matrix for mastering isn't much use, as you'd want a stereo matrix. You can reconfigure the 16x16 to be a stereo 8x8, but you'd need to switch each channel separately.
Our 8x8 stereo relay switcher, with no frills costs about
