I know there were already two releases since your request, but I still remember and I've got it written in my to-do, so I won't forget.

By the way, have you heard of Sleeper (http://wiki.maemo.org/Sleeper)? Maybe it's sufficient for your needs and it's not necessary to implement this feature in OMP if there's already a neat application for this purpose?

Would you like to see in OMP's sleep timer something not available in Sleeper (besides closing the player)?