yes, i'd also go for a one-levelled plastic cage such as the gabber rex or Hagen zoozone. You need space for 2 wheels and a large nesting hut/bridge with more than one entrance. Anything with tubes, levels or separate "rooms" won't be suitable
I have the IMAC fantasy home. My Robo's love it.
I like the fact that it has different level, means if they do have a little fight than can escape each other