Default plugin config to override wp_options?

You could check which options they add (look at the source code) and then simply write a function like this:

/*
Plugin Name:    Mother of all plugins
Plugin URI:  http://wordpress.org/extend/plugins/
Description:    Offers the <code>$all_plugin_options;</code> var to access all predefined plugin options
Author:      Franz Josef Kaiser
Author URI:     http://say-hello-code.com
Version:        0.1
License:        GPL v2 - http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
*/

// Template Tag
function get_all_plugin_options() 
{
    // First we call the class
    $class = new MotherOfAllPlugins;
    $data = $class->predefined_plugin_options()
    return $data;
}

if ( ! class_exists('MotherOfAllPlugins') )
{

class MotherOfAllPlugins
{
    protected $plugin_options;

    public function __construct( $plugin_options )
    {
      // defaults
      $default_options = array(
         'plugin_a' => array(
             'deprecated' => ''
            ,'name'       => 'value'
            ,'key'        => 'value'
          )
        ,'plugin_b' => array(
             'deprecated' => ''
            ,'name'       => 'value'
            ,'key'        => 'value'
          )
      );
      // Now overwrite the 
      $this->plugin_options = array_merge( $default_options, $plugin_options );

      add_action( 'init', 'predefined_plugin_options' );
    }

    function predefined_plugin_options() 
    {

      // Set the flag if we have already done this
      // _EDIT #1:_ This sets an option in the wp_options table containing TRUE if your plugin predef options are already present in the DB
      if ( !get_option( 'predef_plugins_setup' ) === TRUE )
         add_option( 'predef_plugins_setup', TRUE );

      if ( !get_option( 'predef_plugins_setup' ) === TRUE )
      {
         // Add the options for the plugins
         foreach ( $plugin_options as $plugin => $options ) 
         {
            add_option( $plugin, $options, $options['deprecated'], 'yes' );
         }
      }

      // _EDIT #2:_ return the initial array for use in a global
      return $plugin_options
    }

} // END Class MotherOfAllPlugins

} // endif;

To get your plugin options inside your theme:

// Now we take the return value & add it into global scope for further useage.
// This way we can access all options easily without a call to the DB.
// You can now access these values from anywhere in your theme.
$all_plugin_options = get_all_plugin_options();

Be careful to really add the options exactly the way the plugins does it. Else stuff won’t work.