I had an engineer friend drop by at my place yesterday who was very curious what I was up to regarding 3d printing. I showed him our Ecoria projects, he dug the idea a lot, but his main concern was the connectability of the components. He suggested we should go for a system that would allow you to click in the models.
So I started thinking... Another method to connect the panels might be to create holes in the sides of the floor boards and sides/bottoms/tops of the wall panels, and then use connector pins to connect the walls, floors, etc. Very much like how Lego Technic works, like
these.
Made a quick test:

I think I'll move the horizontal connectors (the only ones on the picture) to the sides of the floor and wall panels. This will then also make it possible to do the same to the floor panels which can be used for variants (floor grids, rackfarms, etc), basically the floors that have the detail underneath.
In the middle of the wall panels I can add vertical connector holes (both on bottom and top of the panel), that way it will become very easy to also build multiple levels on top of each other.
I can of course design the pin in such a way that it becomes an official pin or whatever, or keep that very simply so that users can also use just small pipes of plasticcard/wood/brass instead.
But all in all, it has simplified production quite a bit, you only need the panels and a single type of connector.