Marco recently twittered about an app called “Wappalyzer”. This is a browser extension for firefox or chrome that detects the apps and frameworks used in the website you’re viewing.
There is supposedly a detection for OXID eShops, but to me it looks like it’s broken, none of the Shops, even the demoshops, are recognised as OXID. This might be the reason why OXID doesn’t appear here: http://wappalyzer.com/categories/web-shops.
This is the regex responsible:
/<!--.*OXID eShop/, env: /^ox(TopMenu|ModalPopup|LoginBox|InputValidator)/
Maybe someone with a little more regexec experience than myself could have a look at this.