GreenSlate Management. Our company is responsible for developing and managing Omaha’s Blackstone District – a diverse, multi-use community where people can live, work and play. Located at the center of Midtown, the Blackstone District is designed with modern living in mind. Stretching from 42nd to 35th Streets, with only a short walk to a variety of businesses and entertainment. Here you will find everything you need for your comfort and enjoyment.