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If this is for indoor rabbits, you might want to have a look at Nic grid setups, use search terms like "nic grid", "nic cube".
https://www.rabbitsonline.net/threa...hich-nic-cube-set-to-get-zip-ties-etc.102559/
For more diverse ideas use the search term "indoor cages", and select the option [Search titles only].
Outdoors metal rabbit cages are common in breeder and commercial setups. DIY is possible, and 2 storys imho a good idea, the upper one being mostly solid floor.
I use wood hutches outdoors for several reasons, no cage or pen at all exept for door gates to rooms they aren't allowed in for my two house rabbits.
With a little more detail on what you're planning to do you'll get better answers.