Mike:
We have tried to build courses with "no rough" [no mowed rough] several times, where we could. These are the factors that make it easier or more difficult:
1. You're committing to a fairly big acreage of turf to do this [you have to have enough playable area where you can find your ball], so you have to be using a type of grass for the fairways that isn't extra-costly to maintain relative to the roughs. Bermuda, paspalum, and fescue all fit ... perhaps even bluegrass fits. Bentgrass fairways do not lend themselves to this application.
2. In most cases there is just a BIT of mowed rough as a buffer to the native, because it's hard to go straight from 1/2 inch cut to six-inch high native. If you insist on counting that, even Streamsong probably has a little bit of mowed rough.
3. Some superintendents will insist they need x feet of rough buffering the whole course in order to turn the mowers around when they are mowing the fairways at a cross-cut, but that's only because they can't get over doing things the way they've always done them.
4. It does help if you have sandy soil, because of the methods of modern green construction. If you're building on clay, it's hard to have short grass all around the green. You're afraid the greens mix will get contaminated if any water drains from the surrounds onto the green, and even if you do make everything drain away from the green, you've still got clay next to sand, so the fact that it's short turf does not mean the ball will react the same way when it lands. This is part of that old GCA corollary -- everything is harder for Mike Young than it is for me.
(And he's right, it is just hard to work in Georgia clay.)
5. Sandy soil also helps because the native rough tends to manage itself better. On more fertile soils it just keeps getting thicker and you lose balls all the time, so you have to maintain the rough periodically.
6. Sandy soil ALSO helps because you can take some of the tee-to-fairway area right down to open sand where you can still find a topped tee shot. This is probably the place where we've made the most exceptions to the "no rough" concept ... because you have to be able to find topped tee shots, and not many clients want to bring the fairway all the way back to the tees.
We have attempted the "no rough" look now at Ballyneal, Stone Eagle [though you need a bit of rough there because it's impossible to mow right up to the rocks], Sebonack, the Bay of Dreams, Rock Creek, Old Macdonald, and Streamsong.