There are Camelbaks for women. I have one, the Siren, that I have used extensively. It just has a bladder, no backpack. I am generally not good with bottles, so i use it on anything longer than 20 miles or so. When it's very hot, I put Accelerade in my 2 bottles and water in the Camelbak. I bring extra packets of Accelerade in zip locks. In desperation, on my tour in Europe last year, I put Accelerade in my Camelbak. It was 98 in the shade on our last 2 days in Austria. I used my water bottles to douse myself over the head. You're really not supposed to do this (put stuff other than water in the Camelbak), but i bought the Camelbak cleaning system and the long skinny brush cleans the tube well. Then you use a special cleaner to get all of the "bugs" out. I also have a woman specific Camelbak that has a backpack. I've used it hiking or x country skiing for water and gear, but I also adapted it for commuting. I take the bladder out and am able to stash papers, etc in there, since I can't put panniers on my bike. It's ergonomically correct and doesn't feel too heavy, even with my wallet, keys, etc, and extra cycling gear.
I don't mind the extra sweatiness. I'm usually already sweaty! I drink much more than most people and given my spastic ability to use water bottles, I would be dead on the 40-60 mile rides I've done without the Camelbak. I don't really like riding in the heat, but my longest ride was done on a 97 degree day (70 miles). If it's very hot and humid, the air quality here in New England tends to be bad. I will only go out very early in the AM on those days, or go to spin class, so it doesn't cause any asthma problems. This doesn't happen too much, though. I can't imagine riding in AZ. I used to go out at 5 AM and walk when I lived in Tempe and it never was below 100 from June to September.