Suggestions for Short Rack Mount Case

I have a very short equipment rack installed in my server closet. It is only 16 inches deep, fine for most networking uses, but not great for most rack-mount server cases.

I am looking for case suggestions that would fit my rack, 16 inch depth maximum. Height isn't a problem, the rack has a ton of vertical space, over 15U, it's the depth that's an issue.

Thanks!