Here's mine
It's a 110 litre bin tub, a tenner from Homebase
Drilled a load of ventilation holes in it and wired the lid. Hubby made a basic second level from wood we already had.
Dead easy to make and you can buy whatever size you like
have just been looking at the zoozone 1 (which is about as big as we can fit in the space available). Bun Bun - have you added any mesh to the bars on the lid or anything? I can't see how a hammy could climb up there but have been reading other forums etc and they seem to think a hamster could potentially escape between the bars? I will definitely get the biggest cage I can manage.