Apple 10.5 Kernel Extension Caches

OS 10.5 stores extension caches differently from 10.4.  To remove the caches and have them recreated on restart, you need to run the following:

sudo -s
/bin/launchctl unload /System/Library/LaunchDaemons/com.apple.kextd.plist
/bin/rm -rf /System/Library/Caches/
/bin/rm -rf /System/Library/Extensions/Caches/
/bin/rm -rf /System/Library/Extensions.mkext

Then do a reboot to have the caches recreated.
Using radmind to push out a point release and an update to VirtualBox revealed that just removing Extensions.mkext was not enough to clear the cache.