[cypher]

I don't think the gabber rex is still available unless you can get a second hand one, could be wrong though! A zoozone would be ok, you would need to mesh the top, an alaska would be a great size for him but you would have to take care to make is safe if he climbed the bars, it is a little high for a russian but I still wouldn't rule it out.
The hamster heaven isn't a bad size although with the slope on the base it doesn't have as much space as it could have (if that makes sense) something like the barney or alexander from zooplus would work too, narrow bar spacing & plenty of room without being too high.