For archive-product.php and specific vendor info

archive-product.php

<?php
/* This goes somewhere in your archive-product.php template.  This will check if the URL they are on is a vendor store,
 * and if it is, do something, if it isn't, do something else.  Writhing the somethings is up to you. :)
*/

$vendor_shop = urldecode( get_query_var( 'vendor_shop' ) );
$vendor_id   = WCV_Vendors::get_vendor_id( $vendor_shop );
  if ( $vendor_id ) {
    // Do something
  } elseif {
    // Do something else
  }
?>