Decades ago I made a drive enclosure for my IMSAI out of 1/2" MDF. MDF cuts clean, is rigid and very smooth surfaces. The enclosure is the same footprint as the IMSAI chassis so the chassis will fit on it. I think it is 7 inches tall, but you might have to go a little bigger if you have full height drives. It does not have a front of back panel as it is not really needed and allows air to flow around the drives.
The right side has a vertical board that creates an opening for standard 8" drives and I have two Tandon half height double density drives mounted in it. The left side has two 5 1/4" full height floppies and a 20M hard drive. Behind the smaller drives are the power supplies for the drives. One power cord comes out the back along with a bunch of ribbon cables from the drives.
I never did paint it but will probably now that I am building and cleaning up enclosures for the S-100 systems. Time to get things organized.
The little blue cabinets will work for 5 1/4" drives if you remove about 1/8" of plastic from the two vertical sides of the enclosure. I used an air nibbler to cut out the front panel to slide the drives in and used a 1/2" plywood piece with metal straps on the sides to support the rear of the drives. I also used a switcher that just fits in the rear for power. Sure beats bare drives and supplies sitting on the bench with wires strung around.