I had the MPC just sitting on a shelf in the Midicase. Today I finally was able to actually rack it. I was at the local repair shop picking up a regular 1U rack shelf for another project (rack mounting a couple SCSI devices for the MPC), when I spotted a strange looking rack item. Turns out it was the shell for an old Tapco mixer. It was exactly the length and depth of the MPC. I simply drilled a few holes in the bottom, removed a few of the bottom plate screws and attached it to the plate using longer bottom plate screws. Mounted very solidly and holds the MPC at any angle.
Here it in mounted in the case. Sort of looks just like it did before:
If you are wondering how I get to the drive on the front of the MPC, well, I don't. The other part of the project was mounting a SCSI Zip, SCSI CD and SCSI PC card reader on another rack shelf. It was a piece of cake since I have done this type of thing before.