Perceptive questions, I'll see if I can answer them:
First off thanks for taking the time to consider this
I've still not fully decided how and where I'll carry the fuel on this bike(hence the questions). I have a 28l Safari tank and was thinking if the racks/Giantloop thing would work I would carry either 10l on each rack and a bit in a fuel bladder, or 2 Acerbis 5.5l accessory tanks (the square ones that are designed for putting on your triple clamps, a third Acerbis on the triple clamps and some in the fuel bladder, or build a front carrier that fits to the front engine mounting bolts and a few stud holes on the lower frame rails, that will carry another 5l fuel each side (a mate has built some and they work well - tested on the Canning!)
Re water, I have 2 Ortleib water bladders that I was going to chuck in the wings (lowest points) of the Great Basin that I already have. RE the other stuff I pack really light, generally less than 10kg for everything else.
I am also wondering about ways to take the strain off the subfame and have been considering a strut from the upper subframe mounting point at the front to the racks (under tension) to take some of the load off the subframe and put it back on the main frame.
I totally agree that all this weight is not ideal, but some of the Oz desert treks such as the Canning and the Anne Beadell necessitate 800+km of range, with limited water stops.
Check out this thread by a bloke I know, while I think he's pushing the limits a bit here, he's carried a heap of weight on a DRZ with good results (G'day Den..): http://www.advrider.com/forums/showthread.php?t=784942
Hi Tom - apologies for the thread drift, but it's sort off relevant....