Just following back up on this. Big thanks to @fohdeesha for posting the docs and creating the tutorial, and for the help in PM's. Now running a fully functioning 4x 40gb + 8x 10gb + 48x 1gbe switch, for $210.
This sucker is amazing. Well documented, fast as hell. Pulled a sustained 18.6 gb/s from my virtualized freenas to 4x clients on 10gbe, and the raid array was definitely the bottleneck, not the switch. Seems like it will take any optics like a champ, haven't found anything that wouldn't work. Even tired a few DAC cables I had, no issues at all. Best of all? It's noticably quieter than my lb4m, and only uses 9 more watts according to my UPS (no PoE load).