Display 1 post (with a custom Taxonomy) from each category

I have hit a wall with this one and I can’t seem to figure it out…I’m starting to lose hope!
I could really use some help on this one.

Here is what I’m trying to do:
I’m trying to display 1 post from each category, but only if that post has a certain custom taxonomy.

For example…

I’d like to display a post called “Come Together” in the category “Beatles”. BUT I only want that post to display IF it has the custom taxonomy labeled “Abbey Road”

And I’d like it limited to only one post per category.

I believe this is possible, I just can’t seem to make it work right.

Some help would be really, really appreciated.

Thanks!

Here is my code (which is not working)

<?php
$categories=get_categories($all_categories);
foreach($categories as $category) {
$taxonomy = 'session';
$param_type = 'session';
$include_terms = 21; //term ids to include
$post_args=array(
'showposts' => 1, // you can fetch number of articles from each category
'category__in' => array($category->term_id),
'caller_get_posts'=>1,
'include' => $include_terms,
);
$posts=get_posts($taxonomy,$post_args);
if ($posts) {

foreach($posts as $post) {
setup_postdata($post); ?>
<div class="twentyten-artist-post">
	<div class="twentyten-artist-post-image">
		<a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_post_thumbnail(array(20,20), array ('class' => 'alignleft')); ?>
	</div>
	<br><div class="twentyten-artist-post-title">
		<?php
		$category = get_the_category();
		echo $category[0]->cat_name;
		?>
		<?php
		$category = get_the_category();
		echo "(", $category[0]->category_count, ")";
		?>
		</a>
	</div>
	<div class="clear"></div>
 </div>
 <?php
 } // foreach($posts
 } // if ($posts
 } // foreach($categories
?>