You can easily make an override to the product list in admin that would show the stock:-
administrator/templates/isis/html/com_virtuemart/product/default.php
I like to have available and stock ("available" takes note of items that are on order)
$available = $product->product_in_stock - $product->product_ordered;
if ($available < 1){
echo "<div class='stockout'>";
echo "Out ". $available;
} elseif ($available > 1 && $available < $product->low_stock_notification ) {
echo "<div class='stocklow'>";
echo "Low ". $available;
} else {
echo "<div class='stockok'>";
echo "In ". $available;
}
echo "</div>";
echo 'Stk: '.$product->product_in_stock;
The divs just allow me to set colours via css
However if you must have this on the inventory page then the problem is in:-
administrator/components/com_virtuemart/views/inventory/view.html.php
$this->inventorylist = $model->getProductListing();
This assumes that only published is required and can be changed to:-
$this->inventorylist = $model->getProductListing(false,false,false,false);