What possible reason could you have to want to use a parallel port? That is just insane.
Parallel ports (and RS232 serial ports) are rather simple designs that are well documented and easy to program for... great for homebrew projects.
As long as we're on the subject of obscure computer buses, I feel compelled to suggest IBM's MCA and Amiga's Zorro...
And come on, ADB was never really designed for data transfer
It was originally introduced on the Apple IIgs for mice and keyboards and then was adapted for the Mac line. It only transfers a few kilobits/second, so it would take quite a while to transfer the contents of a Hucard.