Thanks to the efforts of myself and others, we have been able to get NGINX into the Ubuntu Main repositories for Trusty 14.04!
Having said this, none of the already-established flavors of nginx are included in Ubuntu Main (nginx-light, nginx-full, nginx-extras, and nginx-naxsi). The Ubuntu Security Team has said that the third-party modules are wildly different in coding and therefore cannot be supported.
To that end, we created a package called nginx-core which has been included in the Main repository. This package contains only the modules that ship with the stock nginx tarball. We do not include any third-party modules with this package, just the modules that come from NGINX upstream.
Thanks to everyone on the MIR an Security teams for all their help in getting nginx into Main!