Hey all, I'm sure some one has thought of/done this before, but for some weird reason I decided to half-heartedly document this project. I've been wanting to add another hard drive in the lower optical drive bay for some time. After seeing the ridiculous prices for a prefabbed bracket, I decided I could try it myself. I started off with an OLD optical drive from a G4 I used to own. Why I still have a IDE optical drive is beyond me. The reason I used an old drive was that the holes for the screws lined up perfectly with the mounting holes in the Mac Pro optical cage. I emptied the guts which just took a few screws and a fair amount of force (those things are tough!) Now I had an empty cage to work with. I marked and cut the back of the top-back of the sleeve to make it flush with the current drive in my Mac as well as making it much easier to plug the SATA cables into. I don't think this was necessary, but it was useful. Next I flipped the bottom plate of the sleeve to give it extra height, since the 2 SATA connecters on the Mac Pro were very close to each other, any extra bit to get it closer to my DVD drives port is a big help. Also, since I flipped the bottom plate, I used some small washers to make up for empty space (see pics). Next I assembled the empty sleeve into the optical cage to tell me where it needed to be mounted. Made a few marks, took it back apart and layed the drive on the bottom plate and traced around it. Then I transferred the screw holes using a paper pattern and drilled them out. I then realized that the SATA connecter is very thick and wouldn't clear the flat plate, so I had to cut out a rectangle in the metal on the back edge (again, see pics). Upon first mounting of the drive, it was nearly directly in contact with the plate, so I added two small washers on each screw to get it away from the plate. This also helped add a bit more height to accomodate the sparse length between the two SATA connectors. All in all, there was a lot of trial and error and it's UGLY as all hell. But once it's installed in the optical cage, you can't even see it. Total time was an afternoon - maybe 3 hours. Drive is running fine, temps are perfectly okay and soon I'll probably install Windows on it. Maybe. Anyways, just thought I'd share my idea for a completely inexpensive, albeit crude, way to add another hard drive to your Mac Pro. I'm sure it would work for an SSD as well. Hope this helps someone!