ようやく httpd-2.1 で 2GB 以上のファイルも扱えるようになるらしい。stable (デフォルト設定)で利用できるようになるのは 2.2 以降らしい…。
Large File Support
httpd is now built with support for files larger than 2Gb on modern 32-bit Unix systems. Support for handling >2Gb request bodies has also been added.
http://httpd.apache.org/docs-2.1/new_features_2_2.html