There was an article about making a fast booting PC (search for it), but I don't think you're going to get much faster. Ever consider just putting the computer to sleep instead of shutting it down all the time?
I'm a strong believer of always shutting my computer off when i'm done using it. I also unplug my charger from the wall when my cell phone is not being charged. I'm trying to conserve. I also like rebooting just to clear everything and let it start fresh when i'm ready to use it.