yes, it is a challenge to fit all the stuff inside a cube tank stand.
I have a 24x24, and used a sump that takes up half that (24x12).
the rest I have a closed loop pump, a kalk reactor, a media reactor and a controller. I was initially planning on sticking in the top off water container in there but that would need a custom narrow and tall container.
I can tell you if you can configure your stand like d2mini where at least 2 sides will open, will make your maintenance life easier. mine doesn't, and I barely have enough clearance to get the skimmer cup out. and if I need to take the skimmer out, I have to drain the sump and take the whole sump out. I have seen some people cut out a notch on their sump so they can get the skimmer out without moving the sump.