Hello, yes for sure there is two rotworms corpses that won´t decay located on a Venore Southern Swamp. To find them exit venore south gate and keep going south. After reaching the swamp troll spawn go to -1 and follow the west path, next go south and west to room with the bodies as it is shown on the screen.
Venore south gate
Swamp Troll cave
Rotworms corpses
They are non-packable.
Sadly I could not locate the dwarf corpses yet, but if I will find it I will let you know for sure.