Sounds a bit backwards to me too, like having an IDE SSD. I guess for old machines in offices that want to put USB pens in it is a good idea, can't say I'd ever heard of them before this thread though. Maybe see if a USB to serial converter exists (i'm assuming you have a COM1/2 port)?
if such a thing exists it would be horribly slow, from memory serial tops out at 192kbps, and thats the shiny ones. cool project though bear, before I discovered DOSBOX I used to have a P166 running DOS 6.22 for running old games on.