There's also these. I don't know how much absorbing the Audioengine wedges are going to do, they're just plastic aren't they?
K, I was a little wrong about the little budget Pioneer sw8mk2 sub. The thickness of the cabinet of the Pioneer is 10/16", while the Mirage is 12/16" (i.e. not that much different). I think it's sort of optical illusion. The Pioneer is a great little sub for the price (definitively better than what came with the old Nano-sat combo).