The rack-mount ears can be moved to the IO side, I have one in front of me. You’ll lose access to the power and reset buttons though, and unless you get the proper power connector, you’ll have a bit of power cord sticking out of the front.
Similar build in this thread if you want more pics: pfSense 1U Rack Build Complete
As far as the mobo goes, you are correct. It looks like the supply has dried up. To be honest though, people liked that board mainly because it had a dual NIC. But for less than $30, you can add a nice quad NIC.