@izzy yes optiplexes (libreboot). i put some realtek ethernet card i bought in the m2 wifi slot. it's on a little ribbon at the back, going to the m2 slot.
this photo shows the same sort of thing, but on a lenovo thinkcentre m920q - which i failed again tonight to get working on libreboot yet.
the wifi one (3rd pic) will be used at home for a wifi->ethernet bridge setup cuz no ethernet at home
gonna do some new tunnel routing setups and i'm experimenting with it on the optiplexes this weekend