I like the idea of an escort quest. I'll combine a few suggestions already made here:
The Dwarven Village contains an NPC called the Dwarven Widow, an incredibly old woman who wanders around the town. If you ask Thrundarr about her, he'll say something about her being "...one of the last who still remembers our lost glory." At first, chatting with her doesn't result in anything particularly interesting. (If she complains about her arthritis, give her some blessed Moss for a small lawful boost.)
To get the Dwarven Widow's quest, you must complete Thrundarr's second quest by going through the Halls, and purified Griff's grave, but must not have dug up any graves in the Dwarven Graveyard, (including Griff's.) If you meet these qualifications and then chat with the Widow, she'll say, "I've heard of your bravery and of your respect for our old ways. My husband died in the siege on the Great Halls, and I've never been able to visit him since we laid him to rest. I heard you've been through the Halls - would you take me to visit him one last time?"
The Widow is fairly slow and fragile, but can be aided by giving her potions of Boost *stat*. Her husband's grave is somewhere in DH2. Escort her to the grave, where she drops some gold, a loaf of dwarven bread, and a potion of booze. Non-dwarven characters will only see the tombstone as dwarven runes. Dwarven characters will find the stone reads, "Here lies Rolf, our greatest warrior, first to fall in the siege on these halls, with scores of our foes slain beneath his axe."
After escorting the widow safely back to the village, she says to you, "Thank you for allowing me to visit my husband one last time. I'll give this to you, since, for me, it only means a longer wait until we're reunited on the other side." She gives you an AoLS.
On your next visit to the Dwarven Village, the Widow is no longer present. If you ask Thrundarr about her, he says that she has died, and thanks you for your kindness to her.
For most characters, that is the end of the story of the Dwarven Widow. However, if you are playing as a dwarf, her story continues a bit. If you become crowned Lawful at the dwarftown altar, (requiring, of course, that you were Lawful the first time you entered Dwarftown,) the priest tells you that the Dwarven Widow named you as her heir. As such, it is your responsibility so see that she is properly laid to rest before you are allowed to claim the inheritance. He gives you the Dwarven Widow's corpse and a tombstone. You must return to the gravesite, dig a hole next to the existing grave, drop the corpse in the hole, then drop the tombstone, sealing the pit and creating the gravesite. (Not sure if this is actually codeable, adjust as needed.) You must also drop some gold, a loaf of dwarven bread, and a potion of booze. (These items will materialize in the shop when the quest is generated, so if you don't have to waste time hunting for them if you didn't have them when receiving the quest.)
If the Widow's corpse rots away before the quest is completed, her ghost appears and scolds you, and the quest is failed. If the quest is completed successfully, when you return to Dwarftown and chat with the priest, he thanks you for allowing her to properly rejoin her ancestors, and gives you Rolf's Helm as your inheritance.
You hear the cries of the crowd: "Freebird!! Freebird!! Freebird!!"
You play some tunes on your lute.