The Tatonka Flightbarrel is tough and spacious, and cabin legal. The bag weighs 1.2kg only and is waterproof. Mine is bright yellow and I can't miss it.
Tatonka Barrel M Travel Bag, Red - Lufthansa WorldShop
Tatonka Barrel / Duffel Travel Bag With Hidden Backpack Straps - Large by Tatonka (Barrel-Large-Duffel)
Tatonka Rain Flap XXL Red | Trekkinn
Tatonka luggage cover 45 - 65 liter | Miscellaneous Goods | Gumtree Australia Brisbane South East - Balmoral | 1301665522