1. In regard to the water while running: Short of the Camel Packs or those fanny pack things with water bottle holders, there is no great way to carry it around. I feel that a weight-bearing exercise such as running makes carrying a great amount of water around just impracticable. I tend to drink a fair amount of fluid before I go on a run. If it will be a long run (over an hour) or on hot days, I will plan my run around parks w/ water fountains or public buildings that have fountains. Some friends of mine will just carry $2 and stop at gas-station if needed.
As noted previously, if you stay well hydrated throughout the day and week, and baring incredibly hot weather, you should be in decent shape without water if you are running 20-60 minutes.
2. I like protein powder as a meal replacement (but only one meal). When I rowed, I needed it as a primary source of affordable protein but I still use it as a law student. Protein (in terms of being a macronutrient) will fill you up for a while. It also is highly dense and complex, so your body actually needs to expend more calories to break digest it.
As long as you are not relying on a powder for most of your daily caloric intake, I think it can be a great way to limit the size and calorie content of 1-2 meals a day. The taste issue can be overcome by buying better protein (I'm a loyal Optimum Nutrition buyer), mixing it with skim milk (water is disgusting), and adding frozen fruit/yogurt to the blender. My breakfast is usually 1.5 scoops of the protein powder (30 grams or so of protein), 12 ounces of skim milk (12 grams protein) and a 3/4 cup of frozen berries. I blend it all together. Fantastic way to start the day and something that will keep me full till my 10:30 snack.