These are the sooters of two South-African fellows, Chris and Hein, currently riding Arround South-Africa as a fundraiser for the Red Cross Childrens Hospital. You can read more about their adventure here:
www.scooteraddicts.co.za
These guys opted for soft saddlebags, resting on the cowels. Before you do this, make sure that they don't restrict air flow to the engine. They could on a classic Vespa for instance. Also, be aware that your scooter, depending on your scooter model and choice of bags, could become very wide. Further, contents in soft saddlebags are not very secure from theft, nor are they well protected in a crash (though the bags may come out pretty decent, or in an easy repairable condition). Lastly, with grit colleting underneath the saddlebags after a while, they will wear the paint on your cowels... but as a true adventurist, you like your ride looking worn and scarred better than nice and shiny anyways.
Here is another option, by two Aussies (the brothers Torsten & Ulick Baumann) going to ride rid arround Australia as a fundraiser for Cure Cancer Australia Foundadtion. They are starting June 13.th 2006. You can read more here:
http://www.rightaroundaustralia.com/index2.htm
They opted for a custom made steel rod frame and Pelican cases(?). In my opinion, they make the scooters wide, and there is also a great risk of bottoming out, especially in turns on uneven surfaces. Lastly, it looks as though you would need to take off the side ases every time you would need to change a tyre or service the engine. On a positive note, the weight distribution is low and lose to the axle (instead of the usual high and rear solutions most often used on sooters).
Here is my solution:
Swapping the bench seat for a saddle seat allowed me to move the box further forward for a better weight distribution. With this loation I don't have to worry about bottoming out panniers in turns, or have sidebags in the way in general. The rack is a bit on the heavy side (6kg). I asked the guy who made it to use angle iron instead of rectangle tubing, but it must have passed him. He also used a bit too heavy steel guaging in my opinion. I bet you ould get it down to 3 kg and also get it a bit narrower (I don't recomend aluminum as capable aluminum welders in some places can be long between... in ase you break them). Another drawback with my solution is that the weight is pretty high up on the scoot, but to me, still preferable to extra width (scooters' cowels make them wide enough as they are).
I allready crashed once with this rack... it saved my scoot.
I really do like the soft saddlebags though. They are heap and easy to fit.