...have you looked into "grouped products"?
...this will allow you to apply a different SKU number to each size.
...on my test development site I have this on my product page to render in grouped products:
<? if ($product->grouped_products->count): ?>
<div>
<? $this->render_partial('shop_grouped_products') ?>
</div>
<? endif ?>
...the partial shows a table list of sizes (sizes are setup on the product in "grouped products")...so the main initial product (or parent product) is the small size...of which "medium" and "large" are added to the small size in "grouped products" tab...
...the "shop_grouped_products" partial is coded like this to render out a table that lists grouped products, the price and the in stock quantity...do note that you will need to modify the "$click_handler" to properly update the product page, mine won't work for you by just a straight copy of the "$click_handler" function:
<h1>Select your <?= h(mb_strtolower($product->grouped_menu_label)) ?></h1>
<input type="hidden" value="<?= $product->id ?>" name="product_id"/>
<table>
<thead>
<tr>
<th class="th_col1"><?= h($product->grouped_menu_label) ?></th>
<th class="th_col2">Price</th>
<th class="th_col3">Stock</th>
</tr>
</thead>
<tbody>
<? $current_product_id = null;
foreach ($product->grouped_products as $grouped_product):
$current_product_id = $current_product_id ? $current_product_id : post('product_id', $grouped_product->id);
$is_current = $current_product_id == $grouped_product->id;
$click_handler = "return $(this).getForm().sendRequest(
'on_action',
{onAfterUpdate: init_effects,
update: {'product_page_div': 'shop_product'},
extraFields: {'product_id': '".$grouped_product->id."'}
})";
?>
<tr onclick="<?= $click_handler ?>" class="<?= $is_current ? 'current' : null ?>">
<th>
<a onclick="<?= $click_handler ?>" href="#">
<?= h($grouped_product->grouped_option_desc) ?>
<? if ($is_current): ?><span class="marker"> - (X)</span><? endif ?>
</a>
</th>
<td>
<a onclick="<?= $click_handler ?>" href="#"><?= format_currency($grouped_product->get_discounted_price()) ?></a>
</td>
<td>
<a onclick="<?= $click_handler ?>" href="#"><?= $grouped_product->in_stock ?></a>
</td>
</tr>
<? endforeach ?>
</tbody>
</table>
...hope this helps!
Andrew
This post has been edited by apepp: 28 January 2012 - 08:11 AM