My brother and I did about 21,000 kms (app 13,000miles) self supported back in 2006 on a pair of px200's.
We had a local guy rig up some loop frames to hold ABS pelican cases. The cases were bigger than we wanted but for the price I couldn't knock them back.
The frame had four attachment points on each side to which the loop bolted. The bags attached to the loops. The loops had to be removable to get to the sidepanels. Held up fine and actually gave us quite a bit of side protection from falls. Won't help you in a crash from the front though...
We were carrying about 50kg of gear as well as an additional 7 litre external tank plumbed into the line so we could switch when the main ran dry. Too much weight as planning for too many potential problems but as the trip progressed, stuff got ditched and the load lightened. Turned out that all the problems we did have were ones we didn't plan for but that's life. I didn't want shitloads of weight hanging off the back and tried to bring it closer to the middle of the bike.
Mostly road but a few hundred k's of dirt. Went through 5 rears and arrived home on the same front.
Tons of pics on the diary pages at http://www.rightaroundaustralia.com/
PM me for any further info. Good luck