Well, how about some
Angry Weapon Enchantments!
Lesser Vehemence
A weapon of lesser vehemence can be wielded by a character who is Raging, in Frenzy, or both as though it were one size category smaller. For example, a Medium sized creature could wield a Large Lesser Vehemence weapon in one hand, or a Huge Vehemence weapon in two.
Vehemence
A weapon of vehemence that is wielded by a character who is Raging, in Frenzy, or both, enlarges by one size category, but can be used as though it had not. For example, a Medium sized creature could wield a Huge Greater Vehemence Fullblade, and upon raging, the weapon would expand to a Gargantuan Fullblade, which could nonetheless be used as though it were a Huge Fullblade.
Greater Vehemence
A weapon of greater vehemence that is wielded by a character who is Raging, in Frenzy, or both, gains all benefits of enlarging one size category (more difficult to disarm, higher damage, but not greater reach), but doesn't actually increase in size, allowing it to be used in more cramped quarters.