i no that u can do this...
make the item
make a npc that gives you the item and starts a timer,
then in 30days it will tele u back and make the items non tradeable to stop ppl making noobs doin it and transfering
isnt the timer cancled once you log out?
only way of doing this really is to set them as normal items, make them non tradable etc and just remove the item/destat them after 30 days.
another option could be to make it non tradable, storable or droppable and put a 30 login timer onto it. then every login the timer counts down, once the timer hits 0 the items are removed. i know this not what you are after but its another solution. that way you wont have people say "i only play at weekends blah blah" the only real problem you will get is if people have there main chars all on one account and switch between them often lol.
then for any server crashes you can just add a login or 2 to there items.
/torni