New lens for my 10D or S2?

[EOSThree]

I have the privelege to work for the Alaska Smokejumpers(no, I don't jump, I am an airplane driver) for another fire season this year. In years past I have carried my G2 with me everywhere with me, and it has served me well. The size is great as the cockpit doesn't have a lot of extra room in it. I just find myself wishing for extra range a lot of the time.
I have a 10D with the following lenses: 17-40 f/4L, 28-105 USM II, 50 f/1.8 mkI, 80-200 f/2.8L, and 300 f/4L. When I do carry my 10D, I use the 50 or the 28-105. If I go with the 80-200, not only is it bulky, but it's too long for interior shots. Due to room and time constraints I don't really want to be changing lenses either. I am thinking the 28-135 IS might be a good choice for me, not only a good gap/walk around lens, but offering me decent range, but keeping the lens short enough for interior shots. I also think the IS will be beneficial with airplane vibration.
The other thought is to keep compact and get an S1 or S2, the S2 being attractive because of it's sensor, digic II, and the other improvements over the S1. S1 attractive purely on price. The large zoom range of the S1/2 is very attractive to me, the IS is also attractive.
If you were in my shoes what would you do? Any cameras/lens suggestions are appreciated.
Here is my friends gallery if you are interested in photographs of my type of work:
http://spotfireimages.com/
This ones an example of what I get: