I've got it down to start minecraft with a batch script and auto-login.
start /high javaw -Xmx2048M -Xms1024M -Djava.library.path=bin/natives -cp bin/minecraft.jar;bin/jinput.jar;bin/lwjgl.jar;bin/lwjgl_util.jar net.minecraft.client.Minecraft "somebody" "password"
However I can't figure out how to start minecraft maximized. There's the magiclauncher which allows me to do that, but I do not want extra applications running when I don't have to. And just 1 simple function is not worth the extra application in my opinion.
So anyway, is there a way to start minecraft with a batch script maximized?