This is a false dilemna if anything.
"How can an architect combat distance off the tee in the real world?"
-Around the green. Placing a tight premium on angle (which has an element of distance to it) and also trajectory. There are greens that are more accepting of a longer shot than a shorter shot. Use the physics of the new ball against the golfer.
-Off the tee. Offset angles and make the golfer either shape a shot to keep it in a playable area or hold something back distance-wise. Another function of using the equipment against the golfer... since when the golfer does miss with the new equipment, he misses A LOT more. Make a shot require a perfect draw or fade, with the straight ball catching trouble.
In general. Make the golfer think and choose... twice, three times... enough to get some doubt in his head. The most effective hole I've ever seen do this is the 1st at Huntingdon Valley.
What golf course would permit them to place bunkers at 280-350 yards from the back tee?
-This is not a creative solution to the distance problem. In fact, it just plays right into the distance problem's hand. The "You get bigger, we'll get bigger" attitude will eventually cause something to break - and equipment won't go first.
What great courses would permit defending par for the longest player at the expense of their general membership?
-False Dilemna... absent proof that the longer player needs more par defense than a general membership and also absent clear definitions of par, defending par, and general membership, I don't see a corellation.
How can an architect serve two, such diverse masters?
You imply disparity where none necessarily exists. Like the above, absent proof of a functional difference I am hesitant to say that architects aren't already serving the two groups.
Tom Doak's challenge isn't very practical. It's been said on this thread before... how many courses actually stretch to 7,500 yards *by design*
Adding new tees and designing a 7,500 yard golf course, to me, are two vastly different things.