No plans, but you can see one of a pair of simple ones I made a few years ago....it's next to the MGB front end in the pic. I needed the storage space, but cabinets along the wall in my little garage had to be narrow - and I wanted to be able to access the content without moving the car - or having a door open against it. The other one is by the rear end. I left a gap between the two to allow the right door to be opened between them.
These are simple, open front plywood boxes about 16" deep. No backs, just 1x4 along the top and bottom to keep 'em square and allow them to be screwed to the studs. They actually rest on a baseboard that sits above the concrete stem wall. That lets me sweep, blow or hose out the garage since they don't sit on the floor - and allows some temporary storage underneath.
The sliding door tracks are attached to the upper and lower edges of the box with glue. They're plastic tracks I found online that are made to fit a 1/4" thick door. You cut the door just a bit taller than the space between the upper and lower tracks, lift the top of the door into the top track, swing the bottom in place and let it drop into place. I actually made doors out of masonite scrap I had on hand - but they've bowed now, so they have a tendency to fall out of the tracks. I need to make new ones out of some stiffer 1/4 plywood so they'll stay straight...
The tops are also covered with masonite just so I can throw it away if it gets too dirty. These cabinets aren't used for very heavy storage (although I do keep jack stands and power tools in one), and aren't used for workbenches....so they're plenty strong for the way they're used....and they were dirt cheap.