Here's an appropriate plugin:
http://forums.bukkit.org/threads/gen-sec-advanced-bans-v0-4-temporary-bans-812.16938/If you decide to give me and D the extra powers you may need these permission nodes:
To work with essentials:
advbans.ban - allow use /bann <nick> [time] [reason]
advbans.banip - allow use /bannip <IP ADDRESS> [time] [reason]
advbans.unbanip -allow use /unbannip <IP ADDRESS>
advbans.unban - allow use /unbann <nick>
advbans.kick - allow use /kickk <nick> [reason]
To work with the standalone plugin:
advbans.bann - allow use /bann <nick> [time] [reason]
advbans.bannip - allow use /bannip <IP ADDRESS> [time] [reason]
advbans.unbannip -allow use /unbannip <IP ADDRESS>
advbans.unbann - allow use /unbann <nick>
advbans.kickk - allow use /kickk <nick> [reason]
I do really think this could increase the quality of the worlds (seemingly low right now). Also it's a good protection from greifing. It also means you keep the right to permanently ban a person. We would simply give you the means to do that while you are not on the server.
Best Regards,
Mrc