I think this is the thread:
http://pdaphonehome.com/forums/ppc-6...acklight+timer
According to the details in the thread, you evidently set your backlight settings to whatever you want them to be, then change
HKEY_CURRENT_USER\ControlPanel\Backlight\LockLevel \LockLevel
from 1 to 0.
I just made the change.. I'll let it run for a couple of days and see if it quits resetting to 10 seconds...