Closets and Home Organization - what to do with excess depth in pantry closet?

I've got a strange "closet" in my kitchen (the house is full of strange closets, actually). It's right next to the door to the basement, and the stairs to the basement turn right into it, creating "steps" in the closet. It surely was not originally a closet; I believe the kitchen counter may have been on that side of the room at that time. Anyway, the closet is about 45" deep, with a shelf at about counter height, as well as a step about a foot high in front of it. (I can post pics if necessary).
When I first moved in, I set about making this closet as useable as possible, so I wired an a/c outlet in it, then moved the microwave into it. I put hooks on the walls and cieling for pans, and put pots and lids on the bottom step. There's a shelf to the back of the closet, where i can stash stuff I don't need too often, as it requires a climb to get to, but the space behind the microwave is wasted, about 24". Any ideas?

Post the pix, but in the meantime, you may could just wall it off at a comfortable height, using the wall to hang stuff on. I am sure it is in a decreasing height as it goes, making it more useless as it goes, so eliminating the space may be the best thing.

Can you utilize the 24 inches from the room on the other side of the wall? Assuming there is a room.
Or you could maybe build a box to fit behind the microwave then mount both the box and microwave on full extension drawer guides that pull out. This would give you an extra storage space. This assumes the closet is wide enough to stand to the side and pull out the microwave.