Well I see there hasn't been any activity for a while on here, so consider this a bump:
On the subject of actually doing something to get the sword, how about you live with your uncle, who says something like: going on a quest? My sword is in the basement". In the place of the chest is a staircase to the basement. Make the basement something like an intro dungeon like Hero Cave in Seasons or Maku Pass in Ages.
Sound good?