I didn't see this post earlier, but I used this recipe about a year ago for a dinner party and it was awesome. I initially chose it over others because it didn't call for packaged crab meat (I can't stand the stuff).
Shrimp and Scallop Enchilada Recipe Inspired by Barrio Cafe's Enchiladas del Mar
Also, instead of cream, I used mostly
whole milk for the sauce (like 2-1/2 cups milk and 1/2 cup cream) in order to cut down on the calories.