I never thought of putting shrimp in a pond. I imagine the temp swings and predatory insects would make short work of them. Still, might be worth a try. I'm very tempted to start a pond right now, but it's just barely February and a few years ago we had snow in March. I don't want to set up a pond only for it to be frozen in a month.
I would love to see a DHG 'Belem' carpet in a pond. With some red plants around the edges... that would be awesome! The only problem would be the intensity of the sunlight might cause some issues without CO2 supplementation.