Attached is the Chamber of Immortality log file. It contains the zone outline, followed by the loc of each column, followed by the loc of the inside line of the staircase. I'm happy to pretty it up if someone would be kind enough to convert it into a png. If someone else would like to, the floor is black granite, walls are red, and the columns are green.
Edit: After a quick scroll down I see that Lanadad already submitted one for this zone. Good deal! Feel free to amend it to include the column locs I've provided at the end of my log file if you'd like.