Q: Can inactive leader's rank be transfered?
A: After 1 week of leader's inactivity he can be impeached with ingots. Seniors can impeach in the first 24 hours after 7 days expire. After 48 hours - anbu, after 72 - elite, and then, finally, normal members. It costs 120 ingots to impeach.
Full information can be found here. Credits to Narutlih for compiling all of this information.
http://forum.naruto.oasgames.com/en/forum.php?mod=viewthread&tid=17912&fromuid=20658