If you want to change the output of anything the get_bloginfo() returns, there’s a couple of filters that make it simple:
(I’m going to leave the practical application brainstorming up to you)
For text:
add_filter( 'bloginfo', 'be_excited', 10, 2 );
function be_excited( $output, $show ) {
if ( 'name' == $show )
$output .= ' OMG BBQ!!! FTW';
return $output;
}
For URLs: change the filter hook to bloginfo_url