Actually I really like that idea! A criceti 100 with a small door added to the front. I think even I could manage to add a smaller door that fits between two of the thicker bars. If I had a small door! Guess you'd have to buy a cheap second hand cage for the doors. It has a huge top opening already. It's probably the biggest hamster barred cage there is. 95 x 57.
What I could never work out - with taking a door off one cage to fix to another, is how to uncurl the tough metal at the bottom where it hinges on. And then curl it back up again.
Ferplast Criceti 100 Hamster Cage
Attachment 53380