That would be interesting. But it would have to be something at least kind of real. Thor's hammer is a little too mythological.... If that makes sense.
But Andvarranaut or Gram (and you could tie that in with the whole Arthurian thing easily) would be very cool. Especially since there is so much you could do with that in a historical sense. Volsunga Saga is fertile ground indeed for an Indy retelling.
Or Skofnung, lots of stories about that sword. Heck you could do a bit of revisionist saga writing and say that it was forged from Gram.
And the cool thing is that these stories have at least shreds of historical truth to them. Its that same possibility that lets us enjoy the other Indy movies.