Maybe milk could be used? :)
http://2.bp.blogspot.com/-wyj6iHUndhg/UXpUk6HxfLI/AAAAAAAACu...
http://thestandardmodel.blogspot.com/2013/04/when-i-was-chil...
It feels like they charge so much not because there would be some principal engineering / technical obstacle but simply because they can. They have been the first who realized something like this can be done (now that LED lighting progressed so far) and for rich customers this is a feature that's highly desirable, so they are willing to pay so much.
They do have a good marketing. Their business model depends on others thinking there is some special magic.
I had to see that reddit post to even start questioning that something like this could be replicated.