[AmityvilleHams]

You could cut large enough panels to allow uninterrupted movement between several bins to increase floor space,and zip tie the bins together.Sometimes a smaller bin between is necessary if the bins don't meet up just right,but the main idea is just making sure nothing is interrupted and that it is done in a way that isn't using tubes and such(as modular cages using tubes and such don't actually increase the floorspace).

Bin modification is fairly simple(doesn't require any extra tools than the standard bin making tools either),and it just happens to be the cheapest way to make cages that can go up to a square meter if not far more!