I could see this a a potential DIY project - paint bulbs black and then carve some of the paint off to let the light shine through. While not specific for outdoor use, these Astral Lights would be a lovely addition to an enclosed porch :)
Patch of Sky – Lamps that share, in real-time, the sky above us
:: Chris Kabel ::Blue Sky Lamp 2014 The lamp re-creates the light of the sky on a sunny day. The blue color of the lamp is caused by exactly the same physical effect that happens when light from the sun enters the earth's atmosphere. Special particles in the resin diffuse the cold light of the power led and disperse the blue lightwaves whilst the orange part of the light beams on.