A lot depends on how you are travelling. If you are the only tour party in the vehicle then a lot of stuff is ok, but if other people are present all this stuff just gets in the way, and the others don't normlly want to wait an hour or so while the gear is set up and sitting to see what eventuates. I assume from that collection you're by yourselves and have time to assemble the cameras and lenses suited to each event.
As my wife is not interested in photography, she would rather watch the interactions and remember these, I take a lot less. One 7D. one wide zoom 17-50 2.8, the 100-400, and if night drives are allowed the 85 1.8. With two shooters I think one more body and either a 70-200 or a longer prime, 500mm or such.
At some point a lot of gear just adds to the hastle of the trip, and not the enjoyment.
Let me add my 2c worth. I just returned from a 5 week photo safari to Namibia. I used five lenses (Tokina 11-16, Canon 24-105, 70-200, 100-400 and 600mm). I shot about 12,000 frames covering a variety of wildlife, landscape, documentary & people and architecture. My most used lenses were the 100-400 (32%), the 70-200 (23%) and the 600 mm (21%).
The 600 mm (Ver I) is a monster, but I'm glad I had it. I'm saving up for the 600 mm V2 for my next trip to Africa. The 100-400 is surprisingly sharp, at least my copy is, but the push-pull zoom takes a bit of work to get used to. I used a 5DII and a 7D so when I needed extra reach, the 600 went on it. Occasionally I wished for more reach (600 +1.4 on a 7D wasn't enough), so I think the 600 V2 with a 2.0 III TC will be great.
Dave - that sounds like a great trip you had! I think you have come a long way since Iceland and have definitely developed an addition to big white lens. Please email me a link to see your pictures. The only reason I am thinking about selling my 100-400 is because I have gotten the 300mm 2.8 again, but yes mine was definitely sharp at 400mm more so than the 70-200 ii with 2xiii. Maybe next trip you should borrow my 800mm.
