A trip to the Apple Genius Store fixed my Mail.app kernel protection failure. My preferences file was corrupt, and even thought I thought I had deleted all mail preference files I missed one of them. Mail.app stores preference list files in at least 3 locations:
The important one to reset is ~\library\Preferences\com.apple.mail.plist. Once this file was deleted, Mail was able to load again.
In order not to loose all of my email accounts, I moved ~\library\Preferences\com.apple.mail.plist to the desktop. Then I restarted Mail.app which caused it to recreate a default, vanilla, preferences file and re-set Mail's internal settings. I exited mail.app and then moved my original plist file to the correct location. Once I re-started mail.app this time, everything worked - and all of my email accounts were available once again.
Horrible error handling on Apple's part, and annoying behavior to store preference files (plist) all over the place.
Thanks to Tom at the Bellevue Apple Genius Bar for helping me get my system running again.