X-Cart Mods: Customer Order History at a Glance for X-Cart:

"X-Cart Customer Order History for XCart will show you exactly what the customer has spent with you on your site. The details are displayed on the the x-cart order detail screen in the administration section. The fastest way to see all products EVER purchased by that customer. Easily see all orders ever placed. Easily see the total amount spent by that customer them in the last XX months. See the total amount spent in total by that customer. Excellent for knowing if a customer is a repeat customer, a loyal customer and also a great way to know if you can upsell them something quickly. Installation is done safely without affecting x-cart!"