It is my contention that the D&D expansion ruleset Sword and Fist, containing additional optional rules primarily for warrior classes, was inadequately playtested in areas. I illustrate this by demonstrating that a sufficiently well trained one legged man in armor can hop at 100 mph uphill both ways in the snow in combat conditions and kill 30 goblins a second while doing so.
Sword and Fist is an expansion book for the D&D role playing game, adding new weapons, feats, prestige classes, and a few new rules. Two of the new prestige classes, the Master Samurai and the Knight Protector of the Realm, gain a feat called Supreme Cleave at level 2 and 3 respectively [S&F p25, p30].
There are three Cleave feats. Ordinary Cleave permits you, if you kill an opponent in hand to hand combat, to make an additional free attack against another opponent in range, but only once per combat round [PHB p80]. Great Cleave lifts the restriction on the number of attacks, but as the character is still fixed in position and there is only a sharply limited number of opponents one can plausibly get into hand to hand combat with at once, the feat is not unreasonable [PHB p82]. Supreme Cleave permits you to take a five foot step between Cleave attacks [S&F p25].
It is evident that Supreme Cleave permits characters to move farther than they would ordinarily move during a round; perhaps much farther. It is not always obvious how much farther, though.
To illustrate, suppose that we have a character with a base attack of +16 or more, giving four attacks. Suppose further that this character has the Ambidexterity, Two Weapon Fighting, and Improved Two Weapon fighting, giving two attacks with his other arm [PHB p83]. Suppose further that this character is armed with two swords of Speed, which grant an extra attack each, bringing the total up to five attacks with one arm and three with the other [DMG p187].
To complete the picture, suppose that this fighter is going against a very large number of creatures that he can kill in one stroke; not unreasonable for a 16th level character, as goblins neatly fit. Suppose also that the fighter hits on a 2+ with each of his attacks; again, not unreasonable.
The fighter will hit and continue hitting as long as he does not roll a 1 on a d20; this is a geometric distribution and statistics tells us the number of expected hits is 20. With 8 attacks this is 160, so 160 goblins will die in six seconds. If the fighter has one level of cleric in a god of Luck, he can reroll one of those misses; so 180 goblins. With a 5' step between attacks, this character has moved 900' in those six seconds; this is an average speed of 102 mph.
This type of movement ignores encumbrance, terrain penalties, and wounds, so in fact a one legged man in extremely adverse conditions would be able to move the same 102 mph that an able man would.
Worse, this is from a standing start to a standing stop, so assuming the gentlest possible acceleration—a constant acceleration to the midpoint and then a constant deceleration—mechanics tells us that the character was moving at 200+ mph, and reached that speed in three seconds from 0 mph. He is also accelerating at 15.24 m/s2, which is almost 2 Gs of acceleration.
It would seem that the full ramifications of Supreme Cleave had not been adequately explored at the time that Sword and Fist was released.
I am indebted to Nate Hellweg for his observations in this matter.