The Arcane Might magic weapon property from the Magic Item compendium says:
Price: +1 bonus
Property: Bows (not crossbows)
Caster Level: 15th
Aura: Strong; (DC 22) transmutation
Activation: Swift (mental)
This elegant, supple bow has intricate runes carved along its length. You can channel the energy of your arcane spells through this bow to make the arrows fired from it more damaging.
As a swift action, you can sacrifice a pre-pared arcane spell from memory (or an unused spell slot if you are a spontaneous arcane caster). Doing so grants a bonus equal to the sacrificed spell’s level on the next damage roll you make with the bow that turn.
Prerequisites: Craft Magic Arms and Armor, greater magic weapon.
Cost to Create: Varies
Is there a balance problem with applying this property to other weapons? To crossbows? To melee weapons?
I understand that the "not crossbows" is there to prevent very low-strength casters from using this. However, this shouldn't be an issue with melee weapons. Is there any reason to discourage this?