Simple ones can't be too hard to make. You could use legos to start and file to shape, then cover with stucco, putty, or something. Or coffee stirring sticks, layered together, covered with putty. That would be a lot of fun to make.
Getting those etchings in the surface is a bigger deal. Could look really cool if they light up with some kind of mystic energy, paint with light blue, red, or green.
