Is there some quick/cheap easy way to transfer files
directly between 2 computers using the USB ports
other than outright networking them?

Why do you need a direct transfer? There are plenty of USB-interface devices --
both RAM-based and HD-based -- that can be used for a transfer.

For example, I can connect my iRiver player to one computer, copy the file to
its hard drive, then connect the player to another computer and retrieve it.