I dream of having big front-opening enclosures like that for my bebes! But I have approximately a zillion (for a pet owner), so they require stacking units. Are there several companies that make those front-opening kinds of enclosures, or just one? How long have they existed? I don’t remember them being widely available for at least the first 10 years of me keeping leos, but I’m not sure.
Re: sand, it sounds like your mind is set, so my response is more for any others reading; I’m not trying to argue. I do agree with @ashleyraeanne and @erie-herps , and I think there’s no benefit to the leos to keeping them on loose sand, and quite possibly harm.
While I am a vet that’s kept leos forever, I’m not a herp vet. I like paper towel, ceramic tile, or reptile tank liners, all of which can be purchased in earth tones. I think slate works as well, but I haven’t read enough about it to be sure. All the substrates I’ve mentioned have virtually zero risk of impaction, are very easy to sanitize, and can be an excellent choice from a financial perspective. (Which one is best varies a lot on the prey you feed, imo.) I have lost a gecko due to substrate ingestion, and nearly lost another. Her name was Trox and I will miss her forever. I had to spend an arm and a leg hospitalizing the other gecko (Penguin), and she was never quite the same (mentally) afterwards- not sure why.
My ABVP Reptile & Amphibian board certified herp vet doesn’t recommend regular sand either, though I do disagree with some of their choices. They recommended hard-packed sand-gravel, especially Excavator clay. I have not used it, and it strikes me as potentially very difficult to clean, but I would probably go that route if I wanted to do bioactive setup for a leo. They mention that a possible alternative would be, “topsoil with no chemicals, fertilizers, manure, vermiculite, or perlite.” They emphasized that they do not recommend calicum sand, silica sand, wood, or coconut products for health reasons. (Recommendations per Dr. Paul Gibbons at Avian & Exotic Veterinary Care.)