Very litte runway is remaining if the takoff weight is runway length limited. Can recall, for example, departing from Rny 27 in Fukuoka Japan at 504,000 pounds (runway limit for the conditions) in a L1011-500 and noting that Vr was within 500 feet of runway end. Also recall the F/O had mentioned that if we tried to stop at V1, we would have ended up in the bay, and he was absolutely right!