Need help with a Skyrim Challenge (Lockpicks)

Currently doing a challenge in Skyrim with a bunch of different self imposed rules.

Basically I'm just wondering if there is any Questline/NPC that rewards the player with lockpicks.
Not lockpicks that can be looted from a chest or a corpse, or sold from a shop.
Just an NPC that directly gives you them at one point or another, just like how Ralof does in Helgen.
When dealt with a locked door, I've just been using the Tower Standing Stone, but I have a Master Lock that I need to get into.

(and I cannot use the Skeleton Key from the Thieves Guild Questline)