Some very old data (the very inital parses done by Romidar & c:o) pegged the minimum/maximum damage values as:
minDamage = 1 + damageBonus
maxDamage = trunc((str + weaponSkill)/100 * damage + damageBonus)
But I'm not sure how accurate those values are post-50; does STR really have that big an impact? According to that, if a lvl 75 Paladin with an unauged 2.0 increases his STR from 100 to 415 his max would go from 455 to 777. That sounds like alot. Also, a minimum damage of what's essentially the damagebonus seems rather low for a 2H weapon. Our 2.0, for example, would land at a minimum damage of 59 at level 75 (if my math is right).