At first we thought we would just reuse an old drive cage of one of the old cases we have lying around. This turned out to be a sub optimal idea. Partly because we hesitated to rip apart a fully functional and non-useless case just to get the cage out and partly because most cages were integrated into the case frame rather than being a separate unit. After some brain storming we found that the housing of a PSU would be perfect in size for holding the 5.25" drives. This was perfect as PSU housings are something we have lying around (from all the PSU:s that have broken over the years). A quick test showed that they seemed made for each other.
We made two cuts in the corners and bent the edges out to make attachment surfaces. These were drilled to fit the attachments hooks and fastening screws. Once again motherboard standoffs were used to make the screw holes. The hooks are two brass bits I found in the Big Box O' Screws we have. I have no idea what they're acctually for, but they came with a computer case at one time. The entire tray consist of two PSU case lids to support three 5.25" drives, but only one is shown in the pictures.
Cutting three small cylindels from aluminum provided some stylish buttons for ejecting the optical drives. The washer stops the button from falling out the front of the case and the drive (or a piece of tape) stops it from falling into the case.
The 3.5" drive cage was something we thought about especially since my brother already has three hard disk drives to put into the case. And with his habit of producing and editing movies on it, it's quite likely there will be a fourth disk sometime in the future. The drive cage obviously needs some cooling, but at the front of the case there is no air intake of any kind. All intakes are at the bottom. The solution was to build a cage out of MDF that would hold the disks in a vertical position above one of the 120 mm intake fans. That should keep things cool enough! Some extra long screws were needed to adapt the 3.5" drives to the 120 mm hole. The drive cage now holds up to four drives with adequate space between them for airflow.
The drives above are three scrap drives we had and the screws are not the ones to be used in the final build as these are way too long.