For 5fg or some other amount

Sure, why not. I've had some threads that I wanted to bring up in some forums after +3months or whatever it is...would be a nice option.

This is restriction to avoid bumping old topics. With suggested option everyone could bump every old topic and mass spam forum by them. If you want bump old topic just ask any JM/TM/MOD for help. We will review if thread can be bumped and we will do it if it is worth.