Much Simpler Grid Loop. Takes the post class and adds the column class to it. Also takes the first x posts and removes that class, which poses as a "featured" type of post. No crazy manipulation, just messing with classes and adding the right size images... Blog Post To come...

gistfile1.php

<?php

add_action('genesis_before_post_title', 'sfws_homepage_teaser_image');
/**
 * Adds Images to Posts in Grid
 *
 * Takes the amount of posts and applies the right size image, whether it's a featured post or a grid block post.
 *
 * @category   Grid Loop
 * @author     Jonathan Perez, SureFireWebServices <[email protected]>
 * @version    1.0
 * @link       http://surefirewebservices.com
 */
function expose_homepage_teaser_image() {
	global $loop_counter; //global post counter
	$paged = get_query_var('paged') ? get_query_var('paged') : 1;
	if ($loop_counter >= 2) { //Everything after the first 2 posts
	printf( '<p><a href="%s">%s</a></p>', get_permalink(), genesis_get_image( array( 'format' => 'html', 'size'=> 'Featured' ) ) );
} else {
printf( '<p><a href="%s">%s</a></p>', get_permalink(), genesis_get_image( array( 'format' => 'html', 'size'=> 'grid-featured' ) ) );
}

}


add_filter('post_class', 'sf_post_class');
/**
 * Add post class filter
 *
 * Uses the column classes to make a grid.
 *
 * @category   Grid Loop
 * @author     Jonathan Perez, SureFireWebServices <[email protected]>
 * @version    1.0
 * @link       http://surefirewebservices.com
 */
function sf_post_class($classes) {    
global $loop_counter; // Post Counter
    
    if ($loop_counter >= 2) { // Everything after the first 2 posts.
	$classes[] = 'one-third';
    }
    if ($loop_counter % 3 == 1) {
      
	$classes[] .= 'last '; //Add Last class to every 3rd post.
    }
    return $classes;
}