Actually you could connect bins together directly instead of buying a wire cage which might not work either
Tubes connecting bins won't help,but direct connections would help.
As for Ikea cages,using four Lack units can make a square meter sized cage for a very reasonable price once you add some melamine for sides and one or two pieces of perspex/acrylic for front panels along with making a lid!However,considering you already have bins and could expand those directly it might be better to stick with bins instead.