I wanted to give it a closed top and found this teardrop shape the best option. I didn't post DoubleTwistLamp 2 because it had a different shape that just wasn't as nice as this one.
Like DoubleTwistLamp1 this lamp is designed for an LED "puck" light. Battery operated lights are about $4 each; simply do a web search for "puck light". This blog page tells where you can get wall powered lights that work very well: http://birkbinnard.com/blog/wall-powered-led-lights/.
This print took 12 hours 33 minutes at a print speed of 100 mm.sec and layer height of 0.205 mm. For details why this is the case see that page or, for more information, this one: http://birkbinnard.com/blog/do-the-twist/.