It was definitely a 3e Dungeon or Dragon article. Can't tell you which, but there are some indexes out there for that.
EDIT: ...oop, sorry, I see Maldin already answered your question at the linked thread.
I could've sworn there was a map, but maybe it was simply that Gary's description of it was so evocative. I haven't used it yet, but that Irongate article is on my mental list of things to steal from some day.