I noticed BuildingGreen added these exterior venetian blinds to the GreenSpec Directory recently. Hella exterior blinds are distributed in the U.S. through Savannah Trims and available in slat sizes of 2", 3.1", and 4". The blinds are aluminum, have lateral tension, and can be controlled manually or electrically. They're slick looking and come in a variety of heights, widths, and colors.
Like architectural mesh, and even more so, Hella exterior venetian blinds can reduce interior glare and heat gain, and thereby, improve the energy efficiency of a building and the performance of workers. The blinds can block up to 90% of incoming light. Plus, since the blinds are on the exterior of the building, any heat that is absorbed by the slats stays outside — no need to run mechanical systems to cool hot blinds.
[+] Hella Exterior Venetian Blinds at GreenSpec Directory.
Photo credits: SkyShield.