You have obviously done some research into this. Here is what I've found works best for our setup.
Go through your bios and test different configurations to see which will allow the fastest boot.
Use NLite to create a Windows XP install, remove a lot of unused junk and tweak the boot settings in the wizard. Don't expect it to work the first time. I've created over 20 images and only 2 work how I wanted.
Run Bootvis, it's a microsoft component that gives you a lot of useful info about what's component is taking the most time to load and will tweak it.
Use Minilogon to replace Winlogon (Do this after running bootvis) This saved me about 7 seconds.
Do all this and your system should boot in under 30 seconds.
I have also been playing with EWF and am still a little confused. I have it enabled, if I try and copy a movie to the hard drive as soon as the ram is full (512mb) the system gives me a ton of errors (Which is what I would expect because nothing can be written to the drive) but when I run my Front End ESXManager and use hibernation with EWF the front end remembers the song it was last playing. How is this possible if nothing is being written to this disk?