Folks, it really *is* the Mages' Guild (nice to know that there's some locked up in the Fighter's Guild too, though).
I got a Thieves' Guild quest from Aengoth the Jeweler in Ald'Ruhn to steal a specific sword from the Mages' Guild there. In the process of hunting around for the sword, I found the armor laying in plain sight in the smith's room.
If your sneak skill is high enough, you can heist it under his nose. If not, the Thieves' Guild quest causes the Mages' Guild to be emptied of all but the guy by the front door, who you can creep by. Bliss!

(It's not a complete set, but IIRC it's the cuirass, shield & helm at least).
[ 01-08-2003, 04:51 PM: Message edited by: Rhea ]