What have I got ? ... checking, it is the "Portable Background Stand Set" from the Morris Co. Chicago, Ill. 60607.
Essentially two stands (maximum height 9' - 10' - ? or so) and a telescoping cross member that will accept both 9" and 12' rolls of seamless paper. All fit in a "bag". This was not an expensive proposition - but it has served well for the last ten years. Just remember that the stands are not pneumatically "buffererd", so use caution in raising and lowering them.
I would *definitely* start with 12' seamless - granted, it is not as portable, but it is awfully easy to run out of background - especially when photographing groups or "full length" or "model in motion" studies. I have both, and use the 12' - out of necessity - 95% of the time.
Incidentally, I have a Ford Taurus, and, with the right-hand side of the back seat folded, the 12' seamless will FIT - over the front seat.