I like Pat's idea of bifurcation, but I would try to accomplish the tougher side by using alternative raking methods. Tom touched on the idea about stirring the sand up before the tournament. I think a more routine system could be used. The bunker sand I mangage plays firm, but raking it a certain way can make it play softer. It takes a little more concentrated effort, but for a special event it certainly seems reasonable if that's what the "tournament committee" wanted.
Overall I get compliments on how our bunker sand plays, becasue it's easy to get the ball up and out of the bunker. I even get other superintendents asking me about how the bunkers are managend becasue their golfers liked it when they played as a guest. It hurts my ego, because I'd rather take questions about how good the greens were. Oh well. Seriously, we have 3 different ways to rake our sand depending on moisture content, so that the bunkers don't play too firm or too soft. For bunker raking, it's sophisticated
, but really doesn't add to our maintenance costs.
My short story is that changing how you rake the sand can influence its' firmness/softness. At Kingsmill we had cheap soft sand, but for the PGA Tour we broomed the bunkers, then we lightly watered them to keep them firm. A different sand and we probably would need to do something different depending on the desired result.
If you want a tool to beef up a course's defense, making the bunkers tougher to play from is something to consider, among others. I think most golfers are plenty challanged just by being in a bunker, so I wouldn't go out of my way to make them tougher on a regular basis.