If you are only collecting larger 1/6 scale figures you can use 1/4" wire cable clamps to adjust the distance between shelves on a detolf. This will give you three 20" height shelves. I collect things of different scales so I have mine set at different distances.
I wouldn't recommend my lighting if you are against visible cables lol
I also have my TH Elvira and Catwoman collection in my entertainment center.