another solution, if you want to spend the money is to hook the camera up to a quantum turbo battery..
http://qtm.com/Turbo/?res_set=yes&res=1280&resh=1024
note they are not cheap but they are excellent products, i have the turbo 2x2 running a Quantum Q-flash and my 1D's off of it and am getting 350-400 shots at least..