After #2 final photo!: Steer clear of thirsty plants... Bold succulents—agaves, aloes & aeonium—give Brooke’s garden the tropical foliage she wanted without the heavy water requirements. There’s also a lot less lawn to be irrigated now—she left just enough grass to spread out a blanket.
This combination of plants won't overwinter in Colorado, but consider the textures and shapes in the leaves-- hardy agaves, yuccas, joshua trees, sedums, and sempervivums would make a spectacular low-water garden.