Reporting Progress Update...
Got the hard drive working and the skin changes in place. My buttons don't work yet, but the LED does. I just need to get the button scripts installed (POWER and RESET). I will say this.. I think I know what caused the corruption. The PiStation build I'm doing has a microSD card ribbon cable, to make access the the SD card external. When I screwed the top down on my case, I crushed one of the wires in the ribbon between the screws. During all of my re-building today, I kept it simple without using that cable. Everything now works right. I tried hooking up the cable again, and sure enough, I get filesystem read/write errors on my screen. So I've ordered a replacement. Cheap enough, but coming from Taiwan so it might take a couple weeks. The other thing I noticed... since the POWER and RESET buttons aren't working yet, I've had the power going straight into the Pi. I've had ZERO undervoltage warnings flash up on my screen. BUT, once I put the Mausberry circuit into the mix, all of a sudden those lightning bolts started showing up. So I don't know if I have a faulty circuit, of it maybe the circuit isn't capable of supporting the volts/amps. I need to try and get in touch with them and see if they can recommend a solution.
As an aside, but related question.. Does the "Powerblock" people use work in a similar fashion? Detecting a button push then sending a signal to the Pi to shut down, then cutting out the power? If so, maybe it can handle the power?