Someone had once given us a very nice folding large dog crate that wasn't being used and it was just sitting in the garage at my mom's. I decided it was much more spacious and sturdy than the wire cage with the plastic bottom and shelves our chins were in when we got them, and since they were now three instead of two things were getting a bit cramped. Plus the cage was hard to clean and access the animals through the little doors, and after joining this forum and learning about how the plastic was so bad for them, I decided I could do better with that crate that was just sitting there collecting dust.
Though the bar spacing was too large for them, this was rectified by essentially wrapping the sides in half inch hardware cloth. This also made the sides easy to affix shelving to with wing nuts or whatever, as the strength of the crate bars supplements the hardware cloth which would otherwise be too flimsy to attach anything to by itself. I also had a wire shelf which wasn't being used, so I cut that to fit just above the pull out metal pan on the bottom as an elevated floor, and covered that in quarter inch hardware cloth as well. This means they are never sitting or standing in soiled litter, which with three of them in one shared space seems like a HUGE improvement over their initial setup. The door to it opens an entire side of the cage, making it MUCH easier to access anything inside and the pan makes it much easier to keep clean since I don't have to dismantle/lift off the whole cage just to change litter.
The crate size is big enough to accommodate three hideouts (one for each chin), several levels of wood and marble shelving, and a huge utility pan wheel (another DIY project using my old roller blade wheel and bearings). The biggest problem I have with it is that I cannot actually attach shelves easily to the far side opposite the door since I can't reach the inside and the outside of that wall at the same time by myself. And I have to crawl inside it myself to reach anything at the back. But the kids seem to be quite happy with, and though it took a little bit of effort on my part to make it suitable, it was far more affordable than spending a couple hundred on a ferret nation type of setup that would be acceptable size and build.
Most cages that are sold now have some type of thing that would have to be altered to make them safest for a chin, so I figure I kinda came out all right in the end both in effort and expense and what they got out of it. It's heavy duty, larger and certainly more functional than a lot of things available for sale that are marketed as small animal habitats. And, it's still collapsible in the end if it needs to be, and put back together without needing a welder. With a little creativity, I think a lot of things could be converted into some pretty amazing setups that were not originally designed for chin purposes. It just takes a little imagination and a little handiwork to realize the potential possibilities...