Is there a hosted e-commerce platform that implements customer reward points?

A client of mine wants to set up an e-commerce site where customers will earn reward points for buying products, with the ability to use those reward points to buy more products. Is there any hosted shopping cart solution that offers this functionality? I’ve looked at 1ShoppingCart, FoxyCart, Shopify and others, but can’t find any hosted cart that offers this. Does anybody know of one? Thanks.

I work mostly with custom eComm applications however I do know that one of my providers does have a hosted version they are working on that does offer reward points based on dollars purchased. I have been working with the application version (non-hosted) for a while now and it is looking promising. They have a freebie version if you want to play.
http://www.bvcommerce.com/

Latest version of its popular Magento Enterprise Edition ecommerce platform, with a much-anticipated customer devotion quality that allows merchants to reward consistent clients.

Hey Lamps Lighting, do you have a link for this one? This sounds interesting to me.

You can try one of those .NET based shopping carts. Try one that integrates easily with your point of sale system or the physical store - for example, a Microsoft RMS integrated shopping cart.

Is the client prepared to host the site themselves (e.g. through a web hosting provider?). If so, you’ll have a lot more options to choose from.

You may find it on X-cart. X-Cart is highly flexible as well as feature rich. There are number of modules available which can easily be integrated with X-Cart shopping cart and enhance its functionality. Pre designed available templates allows to create an extract design for your store or custom design.