Paklite Sorrento Red Expandable Trolley Case Set of 2 for $125 from Peters' of Kensington
These are only the red cases as the black ones have already sold out but I suppose it will make them easier to spot on the conveyor belt.
The set contains:
Medium Expandable Roller Case (42 x 61 x 28cm - weighs 4.2kg).
Large Expandable Roller Case (48 x 69 x 31cm weighs 5kg).