The cages I originally had my chins in were similar to those I have seen at many places: a wooden frame with hardboard plates on the back, bottom, top and sides and mesh on the front. The bottom part of the front was covered with a transparant plastic plate, to prevend wood shavings to fly out of the cage (see pictures below). These cages were fine for a while, but started to have some serious damage after a couple of years. I then had the choice to either do major repairs or get new cages.
Around that time, a friend of mine stopped having chinchillas and had her cages for sale. This was a block of 4 cages, each 1.2 meter wide, 0.8 meter deep and 1.1 meter high. The cage was build from plastified wood, which made it easy to clean and contained shelves of plastified wood for the chins to sit and run on. Over time these shelves were so damaged, that I have replaced them by trespa shelves. This is a very hard (non-chewable) and water resistent material and is therefore perfect for chinchillas. The front of the cages contains a 20 cm wooden board at the bottom (to keep the wood-shavings in) and on top of that an aluminium frame with mesh on it (see picture below). Initially I connected the cages horizontally, to have two really big cages. However, they usually only stayed in one half of the cage so I closed the connections again. Each of the cages now houses 1-3 adult chinchillas. We have recently (dec. 2009) sold 1 set of cages due to a reduction in the number of groups we have.
I've also made a block of two cages using the same set-up that are 1.75 meter wide, 0.8 meter deep and 0.8 meter high (see pictures below). This I find a very good size for the cages. They are still easy to clean, but allow the chins enough space to avoid eachother when they want to. In my opinion, a cage can not be to big, but unfortunately I don't have limitless space at home. Each of these cages houses 3-4 adult chinchillas (1 male with 2-3 females).
In addition I have some Terenziani cages (see picture to the right) which I use to temporarily separate the male (1 week) when one of his females has given birth or to house young chinchillas (from 8 weeks old) until they are picked up or for introductions.
The latest additions are two blocks of 2 cages that are made from alumium frames with trespa sides, back, bottom and roof and a mesh front. The smaller version (left) has two adults per cage while the bigger version has 2-3 adults per cage. These cages are on wheels and cannot be taken apart but are designed so that they can roll through the door of the room and can be easily moved around.