The Salt Lake City GSL Championship is still alive and well. It is an every other year affair in early May. I went last year (2013) and had a great time. The next one is May of 2015. The show is 3 days (Thursday - Saturday), with an awards brunch on Sunday morning.
The quality of the models is excellent, as well as having them judged by a panel of excellent modelers. I have always found them to be very accurate and impartial. The thing that I really like about this show is the other items in addition to the model contest. They have top notch seminars daily, a supplier event (things to buy) and offer free tours of the International Model Car Museum in Sandy, Utah (near Salt Lake City). This is a real interesting place to visit.