Yes, I have experience. I worked for, then owned my own exhibit company. I also have keep many species of varanids to the point of many many generations.
When doing a cage project, you first have to decide what is your REAL intention. To make a display, or to make a usable home for a monitor/s.
Most people who make ornate cages, do so for themselves and not for the animals use or real welfare. Rockwork for a water monitors is not needed what so ever. In many ways, artifical rock is not even good for rock dwelling monitors.
Briefly, articial rock does not feel like rock, feel is more then having a duplicate surface. Or smell like rock, or have the mass and temp holding ability of rock. And lastly does not provide the life a real rock does. The reason I mention this is, reptiles use rocks for the above, not because its a rock. But because of what the rock provides. Like, temp regulation(a particular range of temps) security from predators, a source of food(what else lives in those rocks) and feel. They pick places that are comfortable to them.
Artificial rock does none of that, its only a facade, its for looks only.
Also, something to consider in a very serious way. Artificial rock is either concrete, FRC, or FRP. Most commonly concrete, which means if you lose interest in that monitor, species of monitors, or move. Its more expensive to remove then to install.
If your looking for a really cool display, and want it for looks, then do not consider what will be going in it. Build it, then place in it what will work. By the way, this is how nature works. It has habitats that are fill by life that that finds it useful.
Ok, I could go on for a long time(consulting is paid by the hour) But if it were me, I would build an enclosure that would work for many species. I would keep artificial rock to a minimum, a few boulders that can be easily removed or rearranged. Then I would use natural materials that prove useful to the monitors. Like, I would make the walls to accept paint and paint a mural of the type of habitats. I would of course plan a built the water area, and decorate the banks to appear natural, then use logs, artificial plants and real plants. Of course the most important aspect of any varanid cage is substrate, for a water monitors, a sand bank by a river would do the trick. Then paint the walls as an extenion of whats in the enclosure.
I would imagine in a basement, the cage itself will be fairly small, under 30 by 30ft. So the use of mirrors could be of use. Like, on a side wall, between two trees, this way you are forced to look in the mirror at an angle and it will reflect the back of the cage to make the cage appear almost endless.(I hope you can imagine that, as your going to need a good imagination)
Of course, the most important aspect is the water. Both the feature, if done wrong, it will destroy the house(your basement is the foundation of your house) ALso the whole cage needs to be waterproof as varanids need high humidity and that will also destroy your house. Again, consider this paragraph, you could indeed save you big bucks. Good luck, Cheers
