This has turned into a tough project, like all things that seem simple at first.
The design is basically a three dimensional plaster nest encased in an acrylic box. Pretty simple. However, I wanted to make the creation of the plaster piece easy and repeatable. That meant creating a mold. I found some helpful instructions here. The hard part was tracking down the silicone rubber that was available nearby and in quantities I could afford. None of the local art supply stores had this. I didn’t want to purchase it online because it’s hard to ask questions and get advice, etc.
I finally located a place about 30 miles from my house and made the drive down one day and picked it up. Silicone Rubber is MESSY! Wow. I was kinda surprised how difficult it is to work with without making a huge mess. It comes in two parts that you mix together; the rubber and a catalyst. The catalyst is just liquid consistency and easy to manage. I, of course, spilled it on my driveway and now have to figure out how to get rid of it. 
The rubber is like warmed up taffy or that marshmallow whip stuff you buy at the grocery store. Actually, that’s exactly what it’s like. It’s almost impossible to measure, which you have to do and TOTALLY impossible to clean up afterwards. My measuring cup is wasted.
ANYWAY, I struggled through and completed my first mold. 
It is based on an original model that I created by pouring plaster into a plastic/acrylic box that had clay tunnels laid out in it. The product I used is RTV 500 and it works exactly as described. It does an incredible job of completely seeping into every nook and cranny and making an exact replica of your original.
Here is the finished product:
I actually poured Hydrostone into the mould instead of plaster. I’ve read on the Antfarm message board that it is more mould resistant than plaster. It certainly sets up much harder and is less porous. The design is slightly modified from the first one I posted here. You notice there is a small Fluon-lined chamber for foraging, feeding, etc. Also, the original had trouble with moisture build-up so on top there is a large hole that I have covered with a fine mesh to allow evaporation.
Also, the design is now multisided. So as you see in this shot, 
it’s got chambers for all four sides of the box. Also, you’ll note there is a funnel-topped tube for adding water once evaporation happens.
Underneath we retain the saturation plate separating the Hydrostone block from the water and gravel below.
So, does it work? I know one thing, right off the bat. The chambers and tunnels I’ve created are way too large for smaller species. Also, I’ve heard that in some cases, ants think when they have a large number of chambers available that some chambers are outside the nest and so they deposit waste there. I don’t know what the long term impact of this might be.
Consequently, I’ve decided to go smaller. The Container Store has a smaller sized box that is a bit taller but much slimmer. The problem is, it’s impossible to get your fingers in there to place clay tunnels and chambers on the walls and then pour plaster/Hydrostone into it. So, I am gambling a bit by creating a model from clay to start and will use it to create another mold. The gamble is with spacing. There’s no easy way to make sure the model is the exact size of the internal dimensions of the box. So I am getting as close as possible. It will fit, but won’t be as snug. That could lead to too much moisture exposure or even smaller species drowning. Drowned queens are something I experienced early on it’s a major drag. You always feel responsible.
So, here’s shot of the progress I’ve made. This only has 3 sides of chambers, the 4th side is just one long entrance tunnel. Hopefully this design works and because they are small, they can be easily and quickly expanded by adding another one.
There’s a simple article about this species here if you’ve seen one and want to know more:
