I've just developed a nice little Amazon Remote Cart plugin for ASM2. That application, while excellent didn't come with it's own shopping cart, at least the developer wasn't offering it for free. Now the many sites that don't already have true shopping cart functionality with item update and checkout features using ASM2 can easily drop in my plugin. If you want to view it in action, check out LiveWebShop.com I'll be working on it more as time passes. I think I'll see if there is more demand for it. It's not a bad little start. Version 0.1 is fresh off of my Zend ide.
If you need support or assistance getting the plugin installed, check out the technology forums on www.pureehosting.com . If any other developers want to hook up and take this further, please feel to contact me.