From Einhugur Software:
A REALbasic plugin which implements a Cross platform BinaryStream for larger than 2 GB files . Is MacOS Classic, MacOS X, Win32 and Linux compatible. Is as easy to use as REALbasic's built in BinaryStream. Supports long file names on OS 9 and OS X. Supports Unicode file names on Windows and MacOS X. The plugins supports MacOS Classic, MacOS X, Windows and Linux systems. ($99 is for all of the plugins from the Einhugur plugin pack).