ShopTracker plugin by RuposTel.com for Virtuemart 1.1.x and Virtuemart 2.0.x
We released a plugin for One Page Checkout 1 which tracks your referrals and moves of your customers on your site. Both versions of Virtuemart are supported. This plugin saves the first referal found on your site and also all of the navigation of your customer on your site.
Runs on Joomla 1.5 and Virtuemart 1.1.x, One Page Checkout 1.2.335
June 2013 Update: The plugin now runs on Joomla 2.5 and Virtuemart 2.0.x and renders the output into order details as here: