You could get the recessed light that go into the wall and have the lovered covers used to light stairs and landings.

Another options would be to get some strip flourscent lights. they come in 12, 18, 24" lengths.

There are two styles

One has a cover and is "finished" and designed to use under upper kitchen cabinets. If you use that style open up the stud bay and line the inside with dry wall so that you have a finihed recess and mout the light in there.

Or you could use one that just a strip with a tube and no cover. Mount that inside the bay and then make a cover out of plexiglass or get some of the material for troffer lenses and cut it down.

Thanks for the suggestions. The "stair" lights I've seen are too dim to be worth the trouble in a dark closet. The ones I've seen are typically 20w incandescent and are about as bright as a lighter flame. I was trying to avoid spending the ~$100 it takes to buy the only flourescent version I've found.

I'll look at under-counter lighting and see if there's something that I can use there.