Is it permissible to bequeath more than one-third of the one's property, and is there a Hadith to that effect?

A bequest exceeding one-third of the estate is not permissible, unless it is authorized by the mature and رشيد (of sound judgment) heirs. The proof for this is the authentic hadith (definition) narrated by Sa'd ibn Abi Waqqas, in which the Prophet, peace and blessings be upon him, said to him: "One-third, and one-third is much. Indeed, it is better for you to leave your heirs wealthy than to leave them dependent, begging from people." So, if the heirs authorize it, it becomes valid, because the right belongs to them, and they have waived it.