Christian Weiske has posted information about a feature in the upcoming PHP 5.6 version of the language - large file upload support. This new feature allows files over 4GB to be uploaded correctly.

PHP version 5.6 brings support for file uploads larger than 2GiB. We can say "thank you" to Ralf Lang for the initial patch that fixes bug #44522 , which was open since 2008. During testing uploads of files with a size of 4 - 11GiB on my PHP-CGI setup, I noticed that files above 4GiB did not get uploaded correctly. Michael Wallner was quick to fix that bug, and now 5.6 has fully working support for big files.

PHP 5.6 is still in development and some other new features are slated to be added to it. You can find some of them listed in the RFC section of the PHP wiki.