SimilarSiteSearch is capable of doing search like: "find similar sites to yelp.com in French and must be in Paris", "find sites like amazon.com in UK that doesn't sell books but must sell electronics", and "find similar sites to alibaba.com not for China but for India".
The Next Web Search is devoted to all things search related and is edited by Charles S. Knight, former editor of the blog AltSearchEngines and publisher of over 4,000 posts about alternative search engines.