Leo spent 1,000 hours making these 17kg robotic cosplay wings, modeled on Kayle from League of Legends.
He reports that the wings are surprisingly comfortable, "designed to come forward 10-15 degrees so the centre of gravity would be over my feet." He's worn them for seven-hour stretches with only minor discomfort. His FAQ includes a roadmap for future improvements.
He's not offering this one for sale, though he hasn't ruled out trying to make a production model in the future.