I'd love a retail site that let me search by useful criteria, like country of origin, ingredients (e.g. food must contain or must not contain X), dimensions (no

I'd love a retail site that let me search by useful criteria, like country of origin, ingredients (e.g. food must contain or must not contain X), dimensions (not just '3" to 9"' when I want exactly 6.5"), etc. Amazon has most of the data already listed in tables on the product pages. I want Octopart for everything else.