All right, this is my first post, so please be gentle.
Wouldn't Oakmont be represenative of the classic penal course? In fact, I think it helped introduce the penal school of architecture in America?
In Atlanta, where I am from, PB Dye's, Atlanta National has some very penal holes--1,2,3,6,10,11,12,13, 17 and 18 in particular. On the other holes, while they are hard, a player could play around the hazards so I don't think of the entire course as penal.
Also, Wolf Run in Zionsville, Indiana, a Steve Smyers course, has at least one hole--# 13 I think-- that is a 230 yard par 3 across native grasses and over about thirteen bunkers to a fairly severe green that tilts away and from left to right. I would not describe the entire course as penal, but that hole is a good example of how a penal hole or shot can be quite dramatic and fun, despite being very difficult.
To me, Wolf Run, while maybe more difficult overall than Atlanta National was more interesting as there semed to be more strategic options throughout the course.
I am not sure how much fun a daily dose of 18 holes of the penal school would be for the average golfer, but to have a hole that every now and then says, "You have no choice but to hit it here big boy" at least gets your blood moving!