There's a new Predator video game that features the return of Dutch featuring the voice of Arnie himself. Many fans have wondered what became of that character after the events of the film.
Other loose ends :
Father Callahan from Salem's Lot - later shows up in a Dark Tower novel
The ending of Watchmen - I kinda like using my OWN imagination on this.
Static (Milestone/DC) - supporting character shot in the final issue, the assailant never revealed..
Punisher - early 90's issue. Frank goes to Baltimore and deals with a trashy drug dealing family. The matriach plays the innocent victim and pins the blame on her wimpy husband whom Frank kills. She is probably still active to this day...
and YOUR loose ends?