Australian luggage manufacturer Caribee have several popular wheeled backpacks including their Caribee Fast Track 85, 75 and 45, Caribee Sky Master 80, 70 and 45.
Caribee Fast Track 75 and 85 are available at http://theluggageprofessionals.com.au
The Caribee Fast Track is a wheeled travelpack that is available in 75 or 85 Litre sizes. It has an extendable handle and can be used as a pull along travel bag with the option to convert it to a travel pack when you release the zippered back panel to reveal a full harness system with waist and chest straps. A lot of wheeled backpacks on the market don't have either the waist or chest straps which is not good for your back if you are going to be using it as a backpack more than just occasionaly.
Remarkably the weight of the rolling backpack is only 4kg(75 Litre) and 4.5kg(85 Litre) which isn't much heavier than a regular travelpack. This is in part due to the dobby polymax fabric used in the construction of the wheeled backpack, this fabric is thin and light but is extremely tough due to its weave.
The wheels on the Fast Track are large and have treaded tyre's which are useful when wheeling the backpack over uneven ground or cobbled streets.
The interior of the bag is designed with packing in mind in the main section there are several pockets for smaller items and a detachable hanging toiletry bag there is also a seperate compartment at the base for laundry or shoes. Included with the travel pack is a smaller day pack that attaches to the front of the pack but can also be attached to the shoulder straps and worn on your front (good for security).
Overall the Caribee Fast Track is full of great design features and can be used equally well as a serious travel pack or wheeled bag.