Adam,
I'm glad you enjoyed the show at Grand Coulee -- it remains my favorite of all the shows we've done to date. To the best of our research abilities, it is not only the most powerful RGB projector ever built, it also remains the largest projection of any type in the world with a "screen" abut the size of 55 football fields.
The system continues to use ion lasers becuase of the beam quality requirements; no diode systems come remotely close. Development of fiber lasers has advanced to the point where they could be used to replace the ion lasers, but when I last got pricing in February it would have been about $1.5 million for the lasers *before* getting into the costs of the necessary optical and electronic changes. WAY too much for a retrofit, even for the government!
Unfortunately, the Bureau of Reclamation (operators of the dam) have now been running the same show for 20 years without an update. The soundtrack has help up remarkably well, but the locals are bored of the show and would love a change. The BOR doesn't care what the locals think because the system is intended to education visitors, not amuse the townfolk.
Another company took over maintenance of the system 3 years ago, and things have sadly gone downhill since then; I can no longer recommend that people go visit the show.
-Alex