It's easy enough to move up and down. I didn't want any lights originally and was hoping to squeeze in a few more tanks on the 2nd level. After having it built, I realized that the 2x4 shelf was a good place to hide the fluorescent workshop lights.
The only problem I see with building a 24" deep stand is space issue. If you are tight for space, you may not be able to give up 24"
What's the filtration for the 75 or 55 gallon on top?