Change a config item permanently

[eluser]Genki1[/eluser]
SOLUTION:

I was able to accomplish my goal of setting the CI $config variable at startup using the result of a function, including database queries, and then use the standard CI $this->config->item() statement to access the vars globally throughout my application without making any other changes to my controllers.

The answer is here: http://ellislab.com/forums/viewthread/209989/

Thank you to everyone who contributed and helped.