"Ham-Base Alpha" is finished and in the water. Largest of all modules it can comfortably house 3 to 5 hamsters, with 4 being the recommended number. It contains not just necessities like a water bottle, chewing log and ample food dish but amenities like a running wheel and larger chew toys I happened to see at petsmart and thought they might like. :3
I'm very pleased with how it turned out. It's large enough that it's right on the edge of what is practical to transport and deploy, but that means ample elbow room for the hamsternauts inside. This habitat is truly sufficient for longer term missions, measured in months rather than weeks. The food dish contains enough for that, but I may have to upgrade to a larger water bottle, that remains to be seen.