I am getting an nginx 404 on all pages ending in .html in my test instance, which is in a subdirectory at the root of production. For instance, /test/, /test/contact/ and /test/about-us/ are all good. But /test/women.html, /test/solar-jacket.html, and /test/men.html all return 404. So, no category or product pages. :-( It's the same issue with or without rewrites.
This issue is only on my default store. A second store running on a subdomain has no problem displaying the same product pages.
Edit: It's a problem with ".html". If I enter a bad URL without ".html", I get a Magento 404. All URLs that end with ".html" return nginx 404.