The only problem with the dragon-as-shadow idea is that it would look like it's derived from the Dragonlance novels, where you could always spot a shape-changed dragon because of its shadow, IIRC.
Those novels being rather popular, a lot of people will assume a pinch.
Shame - because I have to admit I like the idea, otherwise.
The hologram idea is a good one - but might be rather expensive. Holograms were never cheap, to my knowledge, though that may well have changed as my knowledge is very out of date, here.
