The solution for speeding up boot time is... <drum roll> Don't do a hard shutdown!
I rarely turn off my TabletPC. Instead I use use the Suspend feature. One of the design specification from Microsoft for a TabletPC was that it had to return from suspend in < 2 seconds. It also had to stay in the Suspend mode on batteries for a minimum of 3 days
I set the power setting to never to into hibernation, so that suspend doesn't "graduate" to hibernation automatically.