Idea for in-the-wall storage

The wall between the laundry room and the water heater room is a supporting wall, and the water heater room itself is low-ceilinged while the laundry room has a high ceiling. I like the idea of using the water heater room (I really must think of a shorter name for it -- water closet? WC?) for storage, but it's like a crawl space -- difficult to get in and out of, especially with bad knees. But storage space is at a premium and I want to use every inch I can.

Hubby has come up with an idea I think is brilliant. Above the door to the WC, high on the laundry room wall, we can put a row of cupboards which won't impact anyone walking past because the ceiling is so high. We can insert cubbies between the studs of the supporting wall, extending into the WC space, with cupboard doors to cover them, and pullout shelves within the cubbies. They would be accessible from the laundry room (no crawling required) but still utilize the WC space. They could be quite deep, too, for storage of canned goods or laundry supplies or tools. I see potential for doing this under the stairs as well, in both stairwells.

Since we seem to be stuck in the tradesperson bottleneck and can't get any contractors to respond within a reasonable timeframe, we are having to park our renovation plans for now. But we could at least be working on this cubby project ourselves so that we can see some sort of progress. It might help allay the impatience I'm grappling with elsewhere. A nice carpentry project would be fun to work on together over the winter.